Depends.. some we pay COD, some are net 30 with generous credit lines.
Most companies will give you net 30 if you have good references and aren't asking for a huge credit line. Net 30 on $5k is one thing. A lot of companies might not want to give you Net 30 on $100k.
A couple months ago I had an order for $90k worth of parts we needed. Wiped out our current vendors and they couldn't meet the deadline on the remaining quantities we needed, so I called and setup an account with a new vendor. We paid them $45k up front and they gave us $45k Net 30. Never dealt with them before, so I was not expecting that. Very impressed, and have ordered a bunch more from them since.