Buy this: Identicator Fingerprint Cardholder https://www.amazon.com/dp/B0050AM5US?ref=ppx_pop_mob_ap_share

Buy this ink: ExcelMark Inkless Thumbprint Pad (1) https://smile.amazon.com/dp/B0043GF5H0/ref=cm_sw_r_cp_api_glt_fabc_9WK0QRDDV4TVB6JZA624?_encoding=UTF8&psc=1

Go here and request the AFT send you some fingerprint cards: https://www.atf.gov/distribution-center-order-form

Fill out the info on the fingerprint cards a few posts down on ARF: https://www.ar15.com/forums/armory/Who-can-do-fingerprint-cards-/17-481492/

I've done 20+ cards this way and they've all been accepted. Don't bother paying anyone for a service you can do at home for $20