FMC is not free and requires purchasing a license (and generally a support contract is also purchased to entitle the customer to upgrades and support).
For a single device running FTD image or and ASA with Firepower service module, using the FDM or ASDM GUI may suffice. Those are free. They can also optionally manage from the cloud with CDO.
It's best to work with your supplier on part numbers. Cisco BOMs include options for what type and term of support and term of licenses etc. that make it difficult to convey in a forum thread. Plus people come back to them years later and wonder why the quoted part numbers are no longer valid.