One of the advantages of selling in a trade show or consumer fair, is that those selling at a low price can make a lot of money as they can tempt customers to make bulk purchases.
For example some products may not be available at the local stores, or the prices will be usually far higher, so the consumer realizes that the deal will not be available when the consumer fair ends, and he or she will often purchase enough to last for a few months, till the next consumer fair.
So those who are selling daily use items at a discounted rate, can make a lot of money if they price their product well. Tomato ketchup, Canned fish manufacturers are offering good deals, however other packaged product suppliers are not using this method for marketing