In Version 1.3/1.3.1: If you have as much many as requested for buying an inventory bag and if you buy an inventory bag, your money first will be decreased, but when you close the inventory menu and go back, your money will be the same amount as it was, before you have purchased a bag, but the bag will be, nevertheless, in the inventory.
Great find again, you have a knack for finding bugs 
Fixed it on our end, but will likely have to wait till next patch till its live.
Hehe… I just love to play Dungeon Quest. It’s honestly my favourite game on android so far. Helping to improve the gaming experience for everyone is the least I can do.
Thank you again SteigerBox!
PS: There is also a tiny bug, when I distribute my stat points, my dps value is always decreased by… idk 66%? as long as I’m distributing stat points. But when I don’t have any stat points left and back out of the menu and then watch my dps again, it is shown properly again. This doesn’t effect any damage outcome.
Yeah it’s not re-calculating properly after a stat point is spent for sure, that’s on our list to fix as well as adding +bolt,+attack to the DPS equation.
Cheers! 
Good to know!