How much it costs is hard to say because there is financial aid. The idea isn't just to enter the PhD program at Chicago. Among other things, MAPPS gives you a chance to work with Chicago faculty who can write rec letters for you. MAPPS is for social sciences, not just econ. There's a lot of flexibility in what courses you can take. If you think becoming a programmer is a great idea, talk to recent graduates being laid off at Facebook, etc.
Right, getting laid off from Facebook as a software engineer means that the next stop is living under a bridge...
These recent grads will resurface at elite tech companies, banks, hedge funds within a few months. Their skillset is extremely valuable in the job market. It's better to be laid off at 23 as a new hire, where it was clear it wasn't a performance issue, than at 43 with 5+ years of tenure at FB.