The REALLY low cost option would be to stay in one of the many hostels near the gulch. This could cost less than $10/night. The BIG problem, though, is that hostels ARE NOT chica friendly! Their market are the backpackers & eco-tourists, not mongers. Since you could not bring girls home, this would limit your activities to the MPs. Not the end of the world but not what I would recommend for a two week stay.
If you could provide a price range that suits your budget, we might be able to recommend lodgings to suit. Off the top of my head, the Hotel Nuevo Johnson comes to mind at $12/night. (
http://www.hotelnuevojohnson.com/index.html ) I would consider it to be located on the edge of the gulch but the price is right. You can search the forum to find reports on the place.
In general, most gringos dress just as they do back home (unfortunately!). Casual clothing is all that is needed unless you plan to go somewhere fancy. Jeans or slacks with a short sleeved polo are almost a gringo uniform!
Hope this helps some.