Scavenging
Is there a tip/dump shop anywhere near you?
The one near us has mountains of old bikes, wheels etc lying around. Take you own tools, and strip off what you want. Some friends of mine up here (Darwin) have built some quite respectable commuters out of frames and parts from the dump shop. As long as you're prepared to put in a bit of time and effort, you can often turn up some gold among the dross.
As an aside, it's also a good resource if you're learning to true/build wheels. You can pick yourself up a handful of old wheels for less than $5 each and practice on them instead of trashing your own pride and joy.