Should I buy a 3ds or wii u?
both?
neither?
I have $600 if that matters but I don't want to use all of it
Buy a 3DS. It honestly doesn't have THAT many awesome games but it certainly has awesome games, most of which came out in 2013, like Animal Crossing: New Leaf, Luigi's Mansion: Dark Moon, Mario & Luigi: Dream Team, Pokemon X and Y, etc.