Say you'll accept an offer for 150K, with details on what you hand over (domain name, code, database), with a post-sale support contract retainer of 20 hours a

Say you'll accept an offer for 150K, with details on what you hand over (domain name, code, database), with a post-sale support contract retainer of 20 hours a month for 250$/hour for as long as they need you for questions.