I bought one a few months ago... I think they look pretty good (especially the ones from "Von Dutch"), but not everybody has to like them!
I bought mine in a regular store, but you can also get 'em at
http://www.vondutch.com ... I had to pay $ 70 for my hat, therefore I have no idea where you wanna get one for under 20 dollars!
You can buy an ordinary trucker hat which is not from "Von Dutch" for a few dollars in almost every "trend" store. But most of them do not look as good (concerning the fit and quality) as the ones from "Von Dutch" ... some of them are pretty hot too tho. You can also buy 'em at the net, just go to Google and type in "trucker hat".