It hasn’t been easy to find a decent barber in Amsterdam; somewhere not too expensive, not too fancy, with friendly, efficient service. There are, of course, plenty of unisex hair salons where a man can get a haircut, but they tend to be a bit pricy and, personally, I prefer going to a more traditional barber. So I’m recommending Neni Kapsalon on Marnixstraat. The Turkish (I think) gentleman that runs the place is very friendly and seems to take a lot of pride in his business. At €13.50 for a haircut, it’s excellent value (for Amsterdam), and most of the time you can walk in off the street without an appointment.
(I once tried a place on Ferdinand Bolstraat that promised a haircut for €12, which seemed like a good price. It seemed somewhat less attractive when the woman cutting my hair pulled on a pair of latex gloves before proceeding. And no, it wasn’t just me that got the latex gloves treatment!)