I do the same, I bought an

with 2 yellow and 1 green controller, with pak and 9 or 10 boxed games(including goldeneye mario 64 and mario party 1) for $15, got it home and found the box had an nes with all peices 4 controllers and 9 nes games under the n64box, it also came with a steering wheel and n64 branded shelf
last weekend, it was 15

1 games for $30 total(2 each) and i left about 12 games i already had there
Your best bet is to go early on a friday and look for block or neighborhood sales, you can hit 5-10 sales before noon if not 11am, and beat the crowds to the good stuff.