I love haircuts abroad. Particularly China where I frequently travel. As others have mentioned, the value and service is incredible... two shampoos, head/neck massage, ear cleaning, etc. And I find that foreign stylists/barbers are often much more skilled with shears and blades than the typical US-trained haircutter (often a formulaic clipper job).

My absolute cheapest haircut was a hole in the wall that I was taken to by a local in Kathmandu in 1999. It cost the equivalent of US 44 cents.