consideration = money paid for the contract.

https://en.wikipedia.org/wiki/Consideration

I don't know why the consideration is $10.   the whole contract needs to be read. 

Legally speaking, a contract needs two party to perform something for each other.   Consideration means that thing performed for each other.   Let's say you donate your farm to the county (or gift to your children), both side sign a contract, saying A gives the farm to B, that contract is invalid if B doesn't give something to A, because contract needs both side to do something, usually in this case, B says, I give A consideration of $1.