Been sort-of having a bit of luck with charity thrifts lately. I think one of the keys to this is not only being consistent with checking, but being there during early hours after they've opened. Most worthwhile donated goods in these stores are probably gone by noon.
Not having much luck finding anything I really want or need, but I'm seeing games more often this way. Came across a stack of NES games the other day, really good labels on them too. Gyruss was the only one I needed, but it was cool nonetheless, seeing this sort of stuff.