Welcome to the Bunnings Workshop community @TMG. It's wonderful to have you join us, and many thanks for your question about updating your backyard.
We can certainly assist with information on How to build a low-level deck, but are there any other surfaces you've seen that you like the look of? If you're willing to remove the bricks, you'd have the option of paving the area. If the bricks are on a solid base, you could perhaps pave over them. You'd need an edging to stop them migrating off the surface. Here are some paving ideas for outdoor entertaining areas.
Depending on the size of the area, you'd likely be able to construct a deck yourself for under the quoted amount. Let us know what you think and I'm sure our helpful members will be ready to assist. Many of the contributed decking projects on the community were constructed by members who had never built a deck before.