Buying Items from Customers

[thetoyjunglefl]

Hello,  I run a retail toy store with a brick and mortar location.  We are starting to buy vintage/collectible toys to resale.   Looking for the best way to run a translation through our POS at the store for these transactions (if there is a way).  

EX.  A customer has a certain toy they want to sell us.  We offer cash for the toy to the customer then resale it.  I'm thinking some sort of "paid out" that we can keep track of easier.

Thanks for any help or suggestions.  I'm kinda at a loss