Accommodation is readily available in most Australian cities and tourist destinations. It comes in a number of different styles.
Camping is a popular pastime. Most caravan parks will rent camping sites by the night, where you can pitch a tent, and these are available in most towns and cities. The caravan park will provide showers and toilets, and sometimes washing and cooking facilities. Sometimes for an additional fee. Expect to pay around $20 for a tent site, and a few dollars per person. You can even find caravan parks right on the beach, with lagoon swimming pools and playgrounds all free for guests.
National parks often provide free camping sites, which expect you to be more self-sufficient. Often toilets are provided and sometimes cold showers. Camping permits are sometimes required at popular parks, with some popular spots filling up during the holidays in summer. In Australia it is common to be within an hours drive of a national park or recreation area that will permit some form of camping, even in the capital cities. Expect to pay around $5–10 per night per person for a camping permit, and national park admission fees in the more popular national parks (e.g.: Wilsons Promontory National Park, Kosciuszko National Park, etc.), however entry and camping is free in the majority of national parks further from population and tourist centres.
Some other camping areas are run by government or even local landowners. Expect around $10 per person per night, depending on the time of year.
You can try your luck sleeping on a beach or pitching a tent overnight in a highway rest area, or out in the bush for a free bed. Most rest areas and beaches prohibit camping and many even prohibit overnight parking to discourage this. Generally the closer you are to civilisation or a tourist area, the greater the chance of being hassled by the authorities.
Camping in state forests is often preferable to national parks if you're after a camping experience over sightseeing, as collecting of your own fire wood is allowed (sometimes felling of trees is permissible dependent on the area) and camping is not restricted to camp sites. Some other activities that are generally allowed in state forests that are not allowed in national parks are: bringing in dogs/pets, open fires, motorbikes and four-wheel driving. State forests are generally free to stay in, although you will need to check locally if public access is allowed.
Hostels and backpackers
Budget hostel-style accommodation with shared bathrooms and often with dormitories is approximately $20–30 per person per night. Facilities usually include a fully equipped kitchen with adequate refrigeration and food storage areas. Most hostels also have living room areas equipped with couches, dining tables, and televisions.
There are several backpacker hostel chains in Australia. If you are staying many nights in the same brand of hostel, consider their discount cards, which usually offer a loyalty bonus on accommodation, and other attraction and tour discounts negotiated by the chain.
Most pubs in Australia offer some form of accommodation. It can vary from very basic shabby rooms, to newly renovated boutique accommodation. The price is usually a good reflection of what you are in for. It is still quite unusual to have a private bathroom, even in the nicer pubs.
Outside of the major centres, the pub is called a Hotel. A motel won't have a public bar. A motel that does have a bar attached is called a Hotel/Motel.
In very small towns local pubs offer the only accommodation available to travellers. Accommodation in these pubs tends to be budget-style with shared bathrooms but private rooms.
Pub accommodation is even available in the centre of Sydney, making getting back to your room after a beer a simple endeavour.
If you travel as a single, and want a private room, pubs usually have single rooms at a discount over a double room. Most motels will charge the same price for one or two people sharing a room.
Typically, motel-style accommodation will have a private room with a bed or number of beds, and a private shower and toilet. Many motels have family rooms, that will usually have a double bed and two single beds in the one room.
Motel rooms in the cities will generally cost upwards from $80. Usually the cost is the same for one or two adults, with any extra people charged an additional fee. Prices for additional children can range from free to $20 per child. During quiet times its not unusual for motels to offer standby discounts.
Most motels will serve a cooked or continental breakfast to your room in the morning, for an additional charge. Some may have a restaurant or serve an evening meal. Some may have a toaster in the room and kettles are widely provided.
All state capitals have a number of 4 or 5 star standard hotels, often with upmarket restaurants, bars, room-service, and other premium hospitality services. Other 2 or 3 star hotels are scattered around the inner-cities and inner suburbs. Best to check local guides and reviews to know what you are in for. Most hotels offer internet connectivity, but usually for an inflated fee. Most hotels (distinct from the country pubs known as hotels) have private bathroom facilities.
Cabins are an economical way for families to stay while travelling. Sometimes built on private land, sometimes in caravan parks, cabins typically have a kitchen / lounge area, and one, two or three bedrooms.
Much as the name suggests, this usually involves a cabin or homestead accommodation on a working property. Suited for a stay of two or more days, this accommodation usually allows you to get a little involved in the running of the farm if you wish. It is common for dinner to be provided in the homestead, and a breakfast pack to be provided to your cabin.
Holiday homes are homes rented by their owners, often using local real estate agents or specialised web sites. Sometimes located in prime positions, but also sometimes in the residential sections of cities and towns. Minimum rental periods of at least 2 days usually apply, rising to a week during periods when they are busy. At a minimum will have bedrooms, a lounge, bathroom.
Bed and Breakfasts tend to be a premium form of accommodation in Australia, often focused on weekend accommodation for couples. They certainly don't offer the discount form of accommodation they do in part of the United Kingdom, and the local motel will usually be cheaper.
Sometimes extra rooms in a person's home, but often a purpose built building. You should expect a cosy, well kept room, a common area, and a cooked breakfast. Possibly private facilities. Substantial discounts often apply for mid-week stays at bed and breakfasts.
There are many true resorts around Australia. Many have lagoon pools, tennis, golf, kids clubs, and other arranged activities. The island of the Whitsundays have a choice of resorts, some occupying entire islands. Port Douglas also has many resorts of a world standard.
Serviced apartments are widely available, for stays as short as one night. Amenities typically include kitchen, washer and dryer, and separate bedrooms.
Caravanning, campervan, motorhome and RV
Caravan parks exist in most towns and cities in Australia that will provide powered and unpowered sites for Caravans. You will commonly see the Grey Nomad brigade on their trips around Australia in motorhomes and caravans.
The camper trailer has also become very popular in Australia. It is perfect for the Australian camping lifestyle, whether it be weekends away or an extended trip into the great outdoors where no facilities exist. You will need to be self-sufficient and carry suitable spares and a good tool kit
Station wagons / Vans
In most parts of Australia it is illegal to sleep in your vehicle but it is possible to get around this by simply rigging up curtains all around the windows so no one can see in from the outside. Trade vans can be picked up for as little as $1,000, with a more trustworthy van setting you back no more than $3,000-$4,000. Add a mattress, pillow, portable gas cooker, cookware and a 20 lt water container and you are off. If you get caught the fine could be as much as $150 each, so do it at you own risk. But if you are strategic in where you stay you probably won't get caught. Just be sensible and don't disturb the locals. Also, be aware of parking restrictions in certain parts of the cities and town, although overnight parking restrictions are rare. The parking inspectors can be ruthless and a $100+ fine is not uncommon.
All cities and towns in Australia have free public toilets. Many parks, and most beaches have free electric BBQ's as well. Popular beaches have fresh water showers to wash the salt water off after you swim, so for those on a tight budget (or for those that just love waking up at the beach) simply wash in the ocean (please do not pollute the ocean or waterways by using detergents or soaps) and rinse off at the showers. Almost all taps in Australia are drinking water, the ones that aren't will be marked. Service stations (petrol/gas) almost always have taps, so these are a good place to refill the water containers each time you refuel.
Some of the best experiences you may have in Australia will be by taking that road on the map that looks like it heads to a beach, creek, waterfall or mountain and following it. You may just find paradise and not another soul in sight. And lucky you, you've got a bed, food and water right there with you.
Travelling in a small group lowers the fuel bill per head, as this will likely be your biggest expense.
Enjoy, and respect the land by taking your rubbish/bottles/cigarette butts with you and disposing of them properly.
(Thanks to WikiVoyage.org)