hmm, i was browsing the bottom forums for hosting solutions and stuff like that. some of those prices are really really cheap. how do they pull it off?

either its really slow, or whatever, but there's no way to make money off those prices.

probably they expect someone will use less bandwidth then others, and still balances?

anyone?

It's been discussed (often).
I'm sure you'll find more threads on the subject if you look around some.
Here's one to get you started http://www.webhostingtalk.com/showthread.php?s=&threadid=42102

Well in my opinion these hosts offer eye catching packages,for example

300MB of space
10GB of bandwith
and all those unlimited things for $5.95 a month,

but they are telling themselfs "users wont use half of this anyways"but when someone does use that much then they try to tell them that there site is to intensive.

Its called overselling. Unfortunately lots of hosts do it and lots close down. :( Quality hosting and bandwidth isn't cheap these days.