I have 800,000 koins, 8000 souls and 500 hearts.
Mainly because I don't like going to the Krypt. I haven't found anything besides Shao Kahn's hammer so I've kinda stagnated. Plus I don't like roaming around and opening chests feels really boring. I much prefer playing towers, getting gear and consumables, and unlocking profile icons and stuff for using different characters.
You need to do 75 fatals and 75 brutals for your 2nd character tower. If you grind that, that's 225 hearts already.