Contract Consideration (aka deposit)

[Account Closed]

What are some creative ways to make a legally binding contract without putting down a sizable deposit?

For example, consideration doesn't have to be money, what else could it be in a wholesale deal?

Frustrated because I negotiated a deal with the seller and we agreed to a price but then I wrote $10 deposit and sent the contract. Now she says she wants 20% at least. If I wouldn't have made light of it I don't think she would say anything.