if you have any TJ Maxx's local, check them. I got a north face backpack there for 20 bucks. and 3 1/2 years later i'm still using it. they had several different styles.
and as for jansport, i used one of those my first 3 years in college, and the last year or so my straps were so worn out it was ridiculous. the straps on my nf are made differently and i don't see them wearing out. so yeah, in my experience there is a difference with the brand.