Remember, you're at a festival and if you or anyone else is selling beef jerky there, ours is gourmet. Artisan/gourmet are the words that I would use on my signs. Typically, festivals and fairs sell their products at a much higher cost and fair/festival goers simply do not mind paying. I say that out of personal experience in going to festivals all the time with my wife. Farmer's markets typical hit you up for 25% mark-ups on their products and what we usually pay for a slice of gourmet pizza at an establishment is usually double at a fair, but you pay because you are with your kids or your family and simply want to try the product.

If a dealer is being charged a wholesale price of 5 bucks per bag I would go 50% higher at a festival where people are simply looking for cool stuff and are prepared to spend money and buy on impulse. If going into a C-store, I'd still shoot for a 25-30% mark up.