How you say thanks to a purchasing agent can and will determine what your next order does or does not look like. Purchasing agents want to be treated as professionals. Nothing will raise their “dark-side” faster than going overboard in thanking them with a nice gift or offering to take them to a nice place for lunch or dinner.
Purchasing agents view what they do as very serious business. Certainly, it’s not inappropriate to offer to take an agent to lunch, especially when the intent is to discuss business first and to say “thanks” second. When you select a place to take them, it should be in line or just slightly better than a place where he or she would normally go if they were planning to go to a lunch. Never offer to take them to a place that is several steps above where they would normally eat. This will definitely be perceived as buying them off. For many purchasing agents, it may even come down to them being allowed to go to an “approved” list of restaurants their management has deemed acceptable when a vendor is taking them out.
The same wisdom applies to gifts. The rule I use is simple — if in doubt, don’t do it! If you do send a gift, ask them first where they would like it sent. This shows you are being upfront and it avoids the perception that you are either buying their business or paying them off.
One gift that will always work is the sincere thank you and a hand written thank you card mailed to them. It’s amazing how the simple act of appreciation and acknowledgment works in terms of building relationships.