PGP question - what do I need?!

Beginners question but not sure what I need to purchase or if I need to purchase anything.

Need to get files from 3rd party via SFTP and the 3rd party will be encrypting the files using PGP.

So I need to be able to generate PGP public key and send to them and I also need to be able to CLI decrypt the files once I get them from their SFTP server.

I am not encrypting anything - just decrypting and will be downloading every night.

Thanks and apologies if this is a stupid question!