Do yourself a really good favour in April and don't buy Mortal Kombat X at launch. Why? Because your going to be ripped off hard.
As the trailer above shows, even a month before release, Mortal Kombat X is already showcasing its first major DLC called the Kombat Pack containing Predator, Jason Voorhees, Tanya and Tremor. This is also on top of Goro, a pre-order exclusive character, costume DLC like the Samurai Pack and Jax is apparently getting Dillon(Carl Wheathers) as an alt skin (DLC of course, would want a complete game noe would we?).
This is getting ridiculous, it's very likely that all this DLC is already on the disc, basically the old Capcom routine (which worked perfectly for them didn't it?). I remember when I got Mortal Kombat Deception and there were 12 character to unlock. It felt rewarding and made you want to play the game more. This just feels cheap and is really just them ripping you off.
So my advice, wait.
PC users, it's guaranteed that this game and it's DLC will be on one of Steam's sales as a bundle or on what ever site/service you purchase your games on. Same goes for console users though you may have to wait longer (and no, I will not have any console vs PC wars in the comments).
But honestly, wait a little bit longer then that because in a year or, lets be honest, 6-8 months from now. There will be a "Komplete Edition" with all of the DLC on, saving you a good $25-$50.