The guys above have pretty much introduced all the basics of cheap detailing. I use a variety of materials for straps, from paper, masking tape, to aluminum foil. I also find that the thicker aluminum foil, generally found in lasagna baking trays, chinese takeout, etc (I'm sure you know what I'm talking about) is a great material for scratchbuilding realistic fenders, muffler guards, anytihng that is constructed out of thin sheet-metal in real life.
No PE bending tool for me. My desk, a steel ruler, and a pair of pliers is all I use. Soldering wire is great for detailing plumbing, but don't forget plain old electrical wire. It comes in pretty much any size you'd ever want, and is sold in quantities that will last you for years.
My one gripe is with punch and die sets. They are ridiculously expensive, but I want one very badly. Most of the self-made ones I've seen seem very flimsy and probably don't provide the best result. The method outlined above might be something to try. Also, up here in Canada, acrylic is the same as it is in the States. It's basically (usually) clear plastic. Not too sure where you can get it though, as that's one area I have yet to explore myself.
One other thing I feel must be mentioned is the water filter canisters that you find in things like Brita water filter, etc. Take the filter, and cut it open. Inside, you'll find small beads and chunks of minerals that are very very small, and can be used for bolts, and other such details. You'll just have to have patience looking for enough parts of relatively similar sizes, but trust me, there's enough in there to go around.
Also, it's been mentioned, but one key faced of modelling has always been stretched sprue. Practice doing it, and you'll be able to create rod in any size you'd like, for nothing.