Forgot to mention that it will probably be "bring your own table" and the $30 gets you space to set it up. If there's a problem someone would probably be able to come up with a folding table.
The tourney is only getting the table space money, and whatever profit they make off the food and beverages. Every dime you make from sales will be yours to keep. The goal is 100 tables, which will raise $3000 for the statue fund, plus a few bucks from food sales. Some of these guys can really work a grill, and make a great chowdah.
$30 for a chance to sell some excess gear, old household good you no longer need or want, or your product along the Canal is really reasonable these days, I would think. The park gets a lot of traffic on weekends, and not just fishermen. Walkers, bikers, rollerbladers--especially rollerbladers

That's why household items will be especially welcome.