+1^ the Scythe Mugen 2 rev.b is the best unit in that price range.
Comes with a high quality silent fan the CM Hyper 212+ is good but the fan is loud.
Another good quiet unit is the Thermalright MUX-120 and it comes with very good thermal compound.
i just bought a cooler for 40 dollars (remember about taxes ) its the zalman 10x performa, i find its works good however i dont have another cooler to test against
what i would say to do is, look at what u can buy in your range (if from a retail store on online)
give the link to the site you are looking at, so we can see what there is and give u ideas what to look at.
i say look at coolers with 120mm fans, ones with options for 2 fans is a good idea, as it allows for better cooling later on for 5 bucks (cost of a fan)
from everywhere i read, the coolermaster 212+ has had great reviews, maxium PC is a fan of it infact. i was unsure of getting it, as the cooler only puts preasure on the center, not even all over the cpu, so cooling is greater in the center, and the cooler can twist (rotate)
for the price, it really cant be beat (maybe the OCZ vendetta 2 on directcanada, its 5 less, looks cooler and does a great job at cooling)
what cpu is it for? (socket type)
so, give us the cpu (socket type), link to what site you will order from