You might not be able to live in Detroit quite as cheaply while building your startup at say Thailand but you can go a pretty long time on $15K. Plus there is a very strong entrepreneur community and great coworking centers like Bamboo.
Just stay away from Barbary St.
Detroit doesn't have a Barbary Street. Unless that is a reference to staying away from the rougher parts of the city. Course that is true in any city. In general if you ask the locals will point out to you the places to avoid.