exhaulst fan suggestions

So i made the mistake of buying a nonreturnable bathroom exhaulst fan. Its a 75cfm fan but ive found that its too wimpy to push air through my DIY pencil cup carbon filter and keep temps down in the cab. I have a hollowed out dresser that stands 24w*18d*42t. Ive priced out fans at my local hydro shop and online but only find huge units or things way too pricey. I only have 100 dollars left to work with and could use a suggestedly better fan if anyone cares to share links or anything usefull. Keep smoke'n!

If your doing it on the cheap check craigslist for a squirrel cage fan some of them even out perform the hydro stores gear

I would go dumpster diveing

I would go to the scrap yard and find one then trade them some junk car parts out of my scrap bin