Problems with car stereo electrical system

Okay basically I have a 2000 ford focus with a regular stereo, not an after market one.

I bought the car used with 96,000 miles on it and when I first bought the car at odd times the radio would turn off. I'd press the power button and it wouldn't come on, but pressing the "2" button would some how make the radio turn back on. So after a year of dealing with that the radio suddenly stopped working. So I took it to advanced auto parts hoping that maybe it was the fuse.

So before I even bought a new fuse I pop'd the old one out to see if the fuse was broken or burnt out. It turns out that it wasn't so I put the old fuse back in and the radio worked fine.

So then about a month later the radio stopped working again, and putting in a new fuse didn't make the radio work either.

So whats my problem? I called instillations unlimited in syracuse and they said they could look at the car but they would charge me 30$, and they could only fix it if it was an actual problem with the radio, or something wrong in the back of the harness. The guy at auto zone said it might be a wiring problem and that I'd have to rip out my whole dash to get it fixed. . . so yeah where do I take the car to fix the damn problem? I just want tunes in my car and I have about 400$ to spend.