IF i look at kits while traveling the ones i am maybe going to buy would be unique ones, maybe location (themed) or something that i do not see every day or locally. i would want something i can't find anywhere else. i would not spend my money on a scrap quilt kit, i have plenty of scraps, i would buy one that was designed by the seller, or that had unique fabrics from the area i am visiting.
and at a festival, i would be much more apt to purchase a table runner type kit; a whole bed quilt kit would really have to be something i just couldn't live without. my experience with craft shows the $10-$25 items sell out pretty quick...the items $50+ not so much. and just an added note...
i do not buy kits! at least not usually, i like picking out my own fabrics...that being said...
I do buy kits when traveling to new places, usually for gifts for the person who is Critter-sitting for me while i'm away, or maybe for a secret sister ect. so i usually will find a unique table runner/placemat kit, or something like that
good luck with your booth