Ralph is a seller of antique books. Marc is a collector of such books. Marc goes to Ralph's store and sees a vintage collection of Harry Potter books. Marc offers Ralph $1,000 for the collection. Ralph declines, but counteroffers with $1500. Desperate, Marc agrees to this price and pays a $200 security deposit for Ralph to retain the books for 1 week until Marc can gain the remaining money. If Marc doesn't show up with the money, Ralph keeps the $200. On the 6th day, Marc shows up with the remaining $1300 and is ready to take ownership of the Harry Potter books. Ralph grows sentimental of his collection, and declines to sell to Marc. Ralph wants to return the $200 security deposit to Marc, but Marc insists they have a contract. Do they have a contract?