Is there anything (soft cover) that i can bring around with me to goodwill/game shops, and check how rare/how much things are worth before i buy them? I'm asking this because at goodwill today, they had a whole bunch of complete Genesis, and NES games for $2.99 a piece, but i didn't know how much any of them were worth, so got none, and instead got a loose Super Mario World for the SNES.
If so, could you give me the name of it, the price of it, and where it can be found.
Thanks.