If you only need to fill a SCUBA tank to 3k psi there is a great deal on a Bauer compressor in Metro Atlanta. $795
https://atlanta.craigslist.org/atl/tls/d/winder-bauer-purus-scuba-compressor/7249943819.html
https://atlanta.craigslist.org/atl/tls/d/winder-bauer-purus-scuba-compressor/7249943819.html