Is it possible to buy,sell and store a smart contract in a wallet?
Yes! It is possible. By indicating the owner of the contract (with the owners wallet address) that is where the contract is "stored," technically who holds the private key to make changes to the contract. From that point the owner can simply change the owner of the contract to a different address. If you've used something like the Mist wallet that allows you to interact with smart contracts, there are a number of built in options that can be interacted with based on authorization. As the owner of the contract, one of the things we provide is the ability to transfer ownership to another wallet.
We've also already built wallets into our game that allow you to manage this.
Let me know if I can provide any additional info, and thanks for the question!