They are not all cheap cheap cheap. I had my livingroom painted recently and the chap charged me £400. Took him 2 days, 9am till 3pm.
That included the paint, two coats on the walls and ceiling, radiators painted, all wood worked painted i.e. cornice, three door frames, bay window, skirting boards etc. And he sanded all the walls and wood work too.
He's been self employed for three years, doesn't advertise, works out of an estate car and has the same ladders and brushs since he started.