Tuna fishing can cost a lot of money. All the gear and line that you have to replace so often makes it impossible to be able to go when ever you would like. Not to mention gas/oil costs, which can be $60+. If you have a comerical licens which i would like to get this summer its not so bad. A fish can sell anywhere from 3$ a pound to 20$ depending on how much fat the meat has. The more fat the higher it sells.