There's a buy & trade store on Haight street in San Francisco.
The drive from SJ to SF is quite the trip, just saying.
I got Socom US NAVY SEALS for PS2 for $1.50. They also had DDR Supernova for $10 and GTA: SA for $20.
I was there looking for PS2 games only but they do have 360, Ps3 and all...