I recently created some signs for a convention table and pasted them on foamcore. Of course, the board did not have any “native” way to stand, so I created these backers. Print onto 8.5″ x 11″ cardstock (makes 2 stands per sheet) and cut along the red lines. Fold inward on the blue lines, glue onto the bottom rear edge of the board, lock the two half-cut ends together, and your foamcore signs should be able to stand on their own. Tested with signs up to 15″ x 20″.
I'm against the use of gimmees (freebies, give-aways, junk, etc) in trade show booths. If you don't start doing it, you'll never have to stop. Just like smoking cigarettes. Both can be bad for your health.
I've had a dozen conversations like this one, but it serves as a good example. I'd had a booth at several B2B trade shows where I was near the same printing company. During this one, they were giving away pads that looked like melon slices. At the top was printed "Honeydew List." They had stacks of other pads out on display, but this was the most popular by far. People were coming by and literally taking away half a dozen at a time, without asking or even being talked to by the booth staff. Word was getting around, apparently, as I heard people coming up the aisle saying, "Those honeydew lists are around here someplace." By the middle of the afternoon, those pads were all gone.