I have 4 case fans running off a small 120vac/12vdc transformer into a bridge. Cost you about $6.00 for them at any decent electronics store. Just solder the ac leads on the transformer to any 2-wire power cord, then the dc to the bridge, then the polarized (+/-) outs on the bridge to the pos/neg on the fans.
You can also find used pc fans of all sizes for $.50 at these electronics stores (again, it has to be a good shop, not Radio Shack).
Anyways, I'm rambling (and stoned). Just thought I'd throw out an alternate idea