Recommendation for a little fan? Just get used computer fan from a computer repair place or, if you know of a place that serves as a drop off for computer recycling/disposal, open up a pc case and remove the fans. Computer expos often have fans as well -- both used and new.
For a power supply, I suggest getting a variable AC/DC adapter. The fan will require DC current -- AC will fry it. Getting a variable adapter will give you some control over how fast the fan spins.