It's amazing people are paying to basically a play a game where everyone is an asshole out to kill them. You could just go out to WalMart or something for free.
It's not an MMO, but I would recommend State of Decay. It has some similarities to Day Z (the open world survival aspect with zombies) only you don't have to deal with sociopaths constantly harassing you. It's not perfect, but it's pretty solid for being something along the lines of Day Z without being multiplayer.