The EPA 608 universal takes about 90-120 minutes online and is free at SkillCat (no affiliation, but I tossed them $50 as a thanks). The 609 (for autos) takes way less time but costs $25 online.

I’ve bought refrigerants online several times over the years without showing any license (even though I hold an EPA 608 and 609). It’s legal to buy for resale, which is probably how suppliers get around checking.