Portsmouth, NH festival is free with a donationn jar making the rounds and some CD tables. The Portland Harbor festival was free. I believe the Bangor International Folk Festival is $15 per day as is NEFFA. Don't see where you are coming from, Conrad.
The most expensive event I attend is the FSGW Getaway - about $130 for three nights accomodations and three meals with snacks per day. CD tables; silent auctions.