I really don't think it's about being a foreigner. We were quoted 5,000 pesos (and ten days work!!!) to get our apartment painted...2 rooms (no more than 45m) (that's not including the tiny kitchen and bathroom which would've been extra). I wasn't even at home so the painter had no idea there was a foreigner living there. He came over, looked at the place and then phoned us with the quote 24 hours later. Of course, when we said no way, he re-quoted us for a "quick job" - 2,000 pesos + 5 days...Christ knows how he managed to drop his price so drastically. In the end, we did it ourselves...400/500 pesos for paint, brushes etc and two weekends. It's not a great job - but it'll do for what we wanted - un "lavado de cara" (we're only renting so didn't want to spend an age on it). I know plenty of people though who painted themselves, took a bit more time and care and it looks just as good as a professional job.