Short answer: cost follows uncertainty and operational consequence. A compact, isolated feature can begin in the hundreds of euros; a connected economy or cross-server system requires individual scoping.
What changes the estimate
Integrations, data migration, custom interfaces, concurrency, version coverage and administrative tooling usually matter more than raw command count.
Ask for assumptions
A useful proposal identifies what is included, what is unknown, the acceptance tests and who owns maintenance. A precise number attached to a vague brief is not reliable.
Budget beyond launch
Reserve capacity for platform updates, live observation and small corrections after players encounter the system at scale.
Explore the related MCMinelab solution