You get to the show, but you’ve forgotten part of your display, bags for people to carry their goods out, selling slips, or enough products to restock when things get low. I see this at the market’s I host and it drives me up the wall. Before you bust a grape(pay for any market) you should already have these basic materials ready to go especially if you where doing business before you even thought about going to market.
The biggest and most embarrassing thing you can do is going to any market and you are not prepared. Before you sign up get an estimate of how many people will be attending (hopefully the coordinator, event manager or trade show owner can provide at least that), find out the demographics where the market will take place, create a list accordingly of products plus a little extra for restock and make sure you have the above items as well. The number one thing that will turn a customer off is if they can’t get a basic bag to put all the stuff they bought from you in.