There is a lot of chatter about the ability ISO-8 from the Shield Training that just completed. I always forget that for many people Marvel War of Heroes is their first trading card game.
For those who don't know this new ISO-8 is meant to be used in the boosting process to give a high percent chance of increasing a skill level. This card is extremely valuable for players looking to level Legendary cards as well as Ultra Rares because of the high cost of leveling. In the highest level cases, this single Ability ISO-8 will offer more of an ability boost percentage than 10 UR cards.
Currently it's assumed that these Ability ISO-8 will mirror the Rage of Bahamut Card Devil Queen which sells for roughly 120HP. Currently in many trades PP has a rough value of 1PP=3HP. Because of this it's safe to assume that the Ability ISO-8 will probably be worth about 40PP in most cases. As people use them to level their legends, the cards will slowly increase in price, probably capping off somewhere around 50PP per.
So, what to do with yours?
If you don't need it and don't have a buyer lined up, I would recommend saving it until the price rises. There is no harm in seeing how high the price will rise because its not likely to drop since it's useful to everybody.
If you do need it, only use it on legend cards and even then for higher levels. It's too rare and valuable of a card to waste on leveling your legend from 1-2.
If you do decide to sell it, I would recommend aiming for at least 35-40PP. Chances are you will get better value out of it in a trade though.