Basically what I notice with that game and the item store is that:
You can purchase this one quest with GP.. and it will take you quite a long time to finish..
But if you pay $1.3 and purcahse the same quest as a pay item.. you have to do a lot less...
They did the same thing with weapons.. weapons are semi-strong, but pay weapons are 5 times stronger and better looking.
(But the majority of the game is player vs monster.. Although you can still do player vs player.)