They have to pay for all the trade show service then. Here are other ideas on bargaining. Try to get accessories. The point it - bargain for higher list price items like accessories and not crating. Also, don't beat them up trying to get free freight.
Freight is a hard cost that they have to pay.
You both win. This is a very competitive business and everyone makes a deal. Even if they just throw in an extra shirtboard or a few gallons of ink, you should always ask for more. All they can do is say no.