I support my local co-op by buying my second hand parts there, and I volunteer there whenever I can.

I support a little student run shop a couple blocks from my place of residence on campus when I need to.

For the most part, my co-op and the little shop don't have what I want/need, so I support the interwebs.

Otherwise, if I really need something that I can't get anywhere else immediately, I go to the overpriced LBS just off campus. I really don't like going there.