I got 20 empty N64 boxes including Mario Kart 64 and Killer Instinct from an estate sale once including (complete) FF7 and other PS1 games all for $20...he even advertised them in the listing. So you never know.
See slow knows what he is talking about Sara. :P
Usually an estate means a person died, so in theory they may have no idea of the value.
But a general rule of thumb would be $1 a box. Obviously there are a lot of factors here, but realistically I would see them either having a cheap group price for the bin or $1 each.
Good luck everyone! I have 2 follow ups tomorrow. I can't believe all 3 people got back to me. I met up and dropped $155 a few minutes ago at my first follow up. Now I need to make a stop at the bank tomorrow when they open.