I'm using a pair of low end Lakes for spin and I can't tell the difference. I've used my MT shoes (upper end/broken in) for spin class and to tell you the truth, both shoes work the same for me.

If you are going out side, buy the best you can afford. They are going to get USED...in spin, you take them to the gym, put them on in class, take them off after and that's it. I bet if I could put cleats on Keds and wear them to spin, I'd be just fine...honest Missliz, the low end cheesy Lakes don't drive me nuts in spin at all....I'd never wear them outside because I mountain bike and they'd get soooo chewed up.

Also, Nashbar techs are pretty knowledgable about riding shoes.
And, Sierratradingpost.com had some SIDI road shoes on sale (Diadora Diablo, too)...problem with Sierra is, they don't have all sizes as they are a close-out/over-stock distributor.
Good luck.
Terry