I'll tell you this: you will get what you pay for. With free ISP's you get banner ads. Not bad for the occasional surfer, but if you're online a lot, it's a major annoyance. There are plenty of sub-$12 ISP's out there, but you're likely going to have to deal with much more busies than normal, and slower throughput.
I work for an ISP that charges $20/mo, and I can tell you they do not make much on each dialup account. Those that charge less can only turn a profit by cutting back somewhere. That usually means there is very little (if any) support, a high user:modem ratio, older equipment, and less bandwidth. It simply is not possible for a budget ISP to offer the same performance of the larger companies by only charging $12 or $10/mo.
Suck it up and pay for a decent ISP. You'll be glad you did.