There are other places to pick up materials. Repairmen often stock a few materials, some lumber yards stock exotic hardwoods, or furniture manufacturers might part with a bit of their wood. Guitar makers in your area also might have enough supplies on hand to set you up, at least for your first guitar. Brazilian rosewood is generally recognized as the best wood for guitar backs and sides, but is very hard to find and you do expect to pay a premium. East Indian rosewood as a second choice is just fine.
Rosewood is difficult to work with.
Finely flamed maple can turn out a guitar of equal quality. Domestic woods such as walnut, unfigured maple, and oak will make a nice instrument. There is a great amount of misinformation floating around about guitar tops. American tradition has it that straight, unfigured, close grained spruce, the closer the better, makes the best top. This isn't necessarily so.