An enjoyable way to spend a day in Amsterdam is to browse through some of the many markets that are spread throughout the city.
The most advertised is the Albert Cuyp Markt, easily accessed via Tram #20. It is in the middle of a quiet street off busy Ferdinand Bolstraat and is open from Monday through Saturday. It is quite large and seems to stretch for about 1/2 mile. There are lots of stalls selling clothes, household products and lots of food items. If you want to try pickled, raw herring topped with onions, this is the place to do it. On both sides of the street are small stores that cater to locals and sell everyday type clothes (no boutiques here), household goods, food, etc. so you can shop 'til you drop. There is even a discount store called Knaackland that has lots of games for kids and other cheap gifts to take home.
The market at Noorderkerk (North Church), just off the Prinsengracht canal is much smaller by comparison. It caters more to the second hand market - books, records, old clothes and other used goods make up the majority of the merchandise. The slogan "one man's junk is another man's treasure" could have been coined for this place. There are a couple of people selling handmade jewellery and the prices are reasonable. If you're looking for retro clothes, this is the place for you. It operates on Monday mornings only.
My B&B host recommended Jordaan Market and said this is where she goes. Size wise, it's a cross between Albert Cuyp and Norderkerk. Lots of produce, flower, cheese and bakery stalls attract locals doing their grocery shopping. There are also toiletries and some clothes vendors too. It is located in the Jordaan section of Amsterdam which used to be a 17th century working class neighbourhood but is now a trendy residential and shopping district. This is also good place to sit at a canal side table and have a drink while people watching.
The most colourful of the markets is the floating flower market on the Singel canal. Open from Monday to Saturday, it consists of a number of permanently moored barges that feature plants and cut flowers of all sizes, shapes and colours. This is the place to buy bulbs for home, although make sure they will pass your country's inspection at Customs. I made the mistake of assuming that bulbs ok'd for import to the U.S. would also be ok in Canada - they weren't so mine were confiscated. This is also a good spot to pick up small cheap souvenirs such as fridge magnets and key chains.
There are many other markets throughout the city. Check with the Tourist Office to find out what's happening, where and when.