Does anyone have any tips on how to tell if a potential supplier is legit. I.E. any documention or licensing that should be available?
If they're US based, I always do this:
Check the WHOIS information on their website. If the information there doesn't match what's on their website, that's a red flag.
Check ripoffreport.com - see if others have been scammed by them.
Search the BBB for the company if possible.
Always speak with them on the phone before you order. A scammer has time to craft their responses in email but can be tripped up on the phone.
Maybe I'm too cautious, but that's what I do. I'm not buying much right now (nothing in the last month) because I'm not finding anyone I feel comfortable with.