What changes the price?
The main drivers are the number of screens and features, how much custom game or business logic is involved, and the integrations you need. A trading bot, a staking interface or a smart contract each add work. So do admin panels, multiple languages, custom animation and migration from an existing system.
Smart contract work and any security review are scoped separately, because the risk is higher when a bug can mean lost funds. See TON smart contracts and jettons and airdrops. Ongoing hosting and third-party fees are your own costs.
