Check out the privately owned and managed offerings at
http://www.amsterdamrentaflat.com/
You can rent any one of two different apartments, as well as a fully contained studio on Reestraat, bordered by the Prinsengracht and Keizergracht canals. That puts the location very close to the Singel and the Wallen, the apartment is very close to the Westertoren and Anna Frank House and is less than 10 minutes walk from Dam Square and the Royal Palace. A very pretty location, and no noisy trams, although you will see the occasional horse drawn carriage.
The most affordable is the Studio @ 60 Euro a night for single occupancy.
Fully furnished with a complete description here
http://www.amsterdamstudio.com/
For the price I can't see any reason at all to stay anywhere else. .
In part due to the success of the Studio there are also two more apartments in the same building.
Bigger and more spacious, thus better suited for up to 6 people is the Amsterdam Choice apartment. Go to
http://www.amsterdamchoice.com/
Now available for short and long term rentals ,the first floor at 21 Reestraat is a luxury maisonette apartment that is the past has been used as a filming location. Scenes from Ocean 12 were shot on Reestraat, as it is just around the corner from the 5 star Pulitzer Sheraton Hotel on the Prinsengracht .
Xaviera Hollander, long time Penthouse columnist and world-renowned as "The Happy Hooker", apparently used the luxury maisonette apartment to shoot a documentary while working as a consultant for BBC.
You can get complete info for the 1st floor apt. at
http://www.amsterdamluxury.com/
I heartily recommend the affordable accomadations at 21 Reestraat, and have stayed there so often that I will always return for the VIP treatment, as well as not having to put up with the Hotel scene. Apartments are the way to go, these privately held and managed flats are a good taste of what Amsterdam has to offer. i don't want to raise peoples expectations too high, but there is really no comparison to hotels. And with the money you save eating in, you can easily afford to eat out when you choose to. I am a pretty frugal person, have stayed in accomodations from dorm style bunks in Hostels, to Hotels ranging from 2-4 stars. I'd rather spend 60 Euro for a fully self contained apartment, than 20 euro for a bed in a hostel anyday. Plus IMO, you can't beat the location or the beautiful scenery of Reestaat. Can you tell I'm really homesick for AMS? I am.