Scope, not the chain, moves the number. By the method used in our free dApp cost calculator (freelancer $350-700 per day, agency $700-1,400 per day with 3 people, testing and project management included), indicative build costs look like this. All before the audit.

Project Team Build time Indicative cost
Vesting program, basic interface Freelancer 2-3 weeks $3,000-5,500
NFT marketplace, production app Agency 3-4 weeks $28,500-57,500
Consumer app on existing protocols, web and mobile Agency 5-7 weeks $48,500-96,500
Lending protocol, 2 programs, oracle Agency 7-10 weeks $73,500-147,000

Where the money goes

  • On-chain programs: cost scales with the number of programs and the complexity of the logic.
  • Frontend: wallet connection, transaction building, error handling and a usable interface.
  • Off-chain infrastructure: RPC providers, indexers, keepers and monitoring.
  • Independent audit: budget it separately, and plan it with the build. For a tiny program it can cost more than the build; for a large lending protocol it is roughly 44-50% of it.
  • Maintenance: usually 15-25% of the build per year.

A short paid discovery phase is the cheapest way to turn a guess into a reliable quote. Indicative figures, not quotes. Full guide and the calculator: https://orivions.com/blog/how-much-does-it-cost-to-build-a-solana-dapp
Checklists for the launch: https://github.com/JakeMalarczyk/solana-security-checklists