I hope they don't add a stupid pop up store thing like all these f2p games. At least make the store at an NPC to make it feel less like an advertisement...this is just wishful thinking most likely.
I'm sure it will be like all the other cash store games. After all if you are deep in a dungeon and find you need a little boost to get that last named, that blinking neon "buy now" sign on your UI (that can't be removed) will be tempting. Who wants to run all the way back to town, then back to the dungeon.