You sell 28 at a time, and you can probably do about 3 trips per minute. 28 x 3 = 84 per minute It really is quick to sell, I wait until I've got 100-200 and then it takes about 5 mins to get to Grand Tree, sell them, and then come back. I'm confused; which is it 3 trips per minute or 1 trip per 5 minutes? The time for the trip should include time to sell. Given the difficulty of buying them, it may be better to kill giant frogs yourself at this point.