Well, I've seen Checkered Puffers go for around $40 at close to adult size. Not sure how well they sell at that though since it is pretty rare to see anyone attempting to sell them around here.
The problem with native species is you typically can't get a general price on them. You simply slap a moderate price on them and hope they sell. A common saltwater puffer (depending on species) tends to range $10-40. Find someone who really wants one and you can maybe jump into the less common medium-sized puffer range of $40-80. Personally, based on the looks of the Checkered/Southern/Northern puffers I'd be surprised if they sold outside of the $40 and below range.