Google cheap Intake fan.Then click shopping it will show you many options. Also like twalte said do you need an intake fan? I run a passive intake on my 5x5 room just fine aswell
U can go to ur local good will and buy a hous fan for 4-15 dollars cut some cardboard up and make a funnel down to size intak pipe or port and hook it up it cheap and efficient doesn't look presentable but works if ur on a budget
home depot / lowes sell cheap, inline duct booster fans.. they're not the best of quality, nor all that powerful, but they'll do a decent job in a pinch until you can afford a quality fan..