At this point, there seems to be a handful of vendors, both domestic and cn ship, that post promos here on a regular basis.
To me there is a big benefit to us consolidating our purchases around these vendors, especially in promos where a specific batch is being shipped.
1) it gives us leverage to demand good behavior, fast shipping and responsiveness to any issues.
2) it results in aggressive pricing and offen allowances for 3rd Party testing cost reimbursement.
3) A track record around specific batches quickly gets published - between initial testing, 3rd party testing and group usage, it’s about as confident as you can get.
I’m not going to tell anyone what to do, but I don’t see any benefits - cost, availability, or reliability - buying outside that handful of vendors.