It was in the 25m range before they increased the drop rate of the powerscrolls, during which time you had to combine 8 105 powerscrolls (which were the only ones that are dropping, 110 drop was a myth) and 105 ones were being sold for 3-4m so 8x3m - 8x4m = 24 - 32m price range. However, with the Publish 69, "Fishing Power scrolls above 105 made easier to get".
This doesnt mean you cant sell for a high price since we all know fishmonger quests are not fun to do. The supply depends on the fishers constantly sailing between towns and completing these quests. You might think of reducing the starting bid however.