Most of the pawn-shops near me are pretty up-to-date & price-savvy about the prices that they'll buy & sell their video games for.
IIRC, I've got a few PSX RPG's (C.I.B.) like FF: Anthology & Chronicles, FF VI, VII, VIII, & IX, Vagrant Story, and Koudelka between $10 - $20 each -SO- A little better than average, but nothing spectactular
My personal (best) finds & experiences have been...garage & yard sales.
Admittedly, I'd estimate that while ~98 out of 100 of 'em are complete wastes of time & gas...BUT...the absolutely & amazingly lucky "miracle-finds" (aka "the *other* 2%" of them) are usually just...
*SO* *DAMNED* *GOOD*...
...That they'll keep me going to the next set of 100 sales - looking, hoping, and praying for some more of those "2%-ers"