Camping gear from Kmart or TargetCamping gear in Australia varies for quality and price. Brands like Jackaroo and Coleman have been around for many years and have a high quality standard.
If you step into a city camping / hiking store you will find even more premium brands of hiking gear, tents, and camping equipment. Ultra well designed and light weight, the city hiking stores are very much oriented to the hard core, brand driven hiker with the prices to match. Beware that the carbon fibre cutlery and crockery is going to cost you a backpacker's week's wages.
There are plenty of alternatives. Oztrail is a camping gear brand that you will find everywhere. It is typical for department stores such as Kmart, Target and Big W to stock a full range of OzTrail along side their own cut-price brands.
Australian shops are duty bound to stock products of a reasonable quality, so you can expect good quality and reliability from even their cut-price "home brand" camp equipment. Australian department stores also have exchange or refund policies that are aimed at customer satisfaction. Even better if you have taken a copy of the receipt on your smart phone at the time of purchase, so you can show the customer service person that you DID purchase the product at one of their stores.
In the end you can expect to pay $20 - $30 for an easy to erect two man tent and just $9 for an single inflatable mattress at a Australian department store.