This is a Quora question that I was asked to answer. My answer is as follows:
It depends on who is your end-customer and their creditworthiness at tradeshows.
If you are selling wholesale to established businesses, then you could simply offer a show special (like 20% discount) and provide a cut-off date before the discount goes away. I have offered 2-weeks following the tradeshow as my cutoff point, but it can be whatever time you want. Wholesale buyers must submit a PO within that time frame. By doing it this way, I am saving myself the hassle of trying to process orders at the show. Further, I am at the show to sell, promote and talk to customers; processing orders takes away from the valuable sales time.
If you are selling to buyers who place small orders or you cannot get a sense for their creditworthiness, you could offer the same listed above, except payment is due before you ship the merchandise. I have used credit card processing in the past to do this. You could use something as simple as Paypal or Square on your mobile/tablet to process orders at the show or sometime thereafter. But again, if you plan to process orders this way at the show, it might be best to have someone else do that exclusively at your booth while you focus on interacting with your customers.
I post what I see and do in consumer products. But I am just one person with my own perspective. I want your opinion and observations from your point of view. Please comment below so I and others can learn. Thank you!