I am playing this game on my main device, and am now lvl 70, and trying to gather souls for a new 12 items pack.
The thing is I installed the cracked version on another device, I upgraded my hero up to lvl 65, and tried to see how many 12 items packs I need to buy in order to have all inferno set.
I ended up buying 150-200 12 items packs. that is 15x100 souls = 1500 souls. At least.
On my main device, I have already bought about 6, nd I am gathering now for a 7th. So either you invest a lot of money in the game just to have the inferno gear, or don't invest nothing and play with what you get from drops...