The Waterlooplein Market is listed in all the guide books. We went on Saturday and the weather was great. Outdoor markets are the best in sunny weather because the people watching definitely improves.The market is a great place. It has dealers that are selling what I loosely call Trash and Treasure, which is booths that are loaded with stuff that is best illustrated by the photos I’ve uploaded.
We bought sunglasses for 6 euro, we bought some little wooden stamps that my nieces were thrilled with, we looked at all kinds of clothes and leather (and pleather or faux leather) goods, we tried some fries, we looked at tools, we looked at arts and crafts kind of stuff and bought a few more kitschy souvenirs for half the cost of buying them in a store.
You can reach the market via the tram. It is a short walk (about half a city block) from the tram stop.