Outside the Center (Amsterdam) for cheaper

try looking at hostels. Many have double rooms with baths. Hostelworld.com is a good place to start. Along with descriptions, there are usually reviews that give you a good idea of what awaits you. Some hostels are for the partiers, but some are more for serious travelers.

Also look at biddingfortravel.com as a start to name-your-own-price on priceline.com. While I haven't used it for awhile, I did get a 4-star room in the center for a Saturday night in June 2012 for about $100 when most hotels wouldn't even let rooms for a single night on the weekend.

It may be easier to find places using the currency of the land. What you are looking for is in the vicinity of €78 or less. Prices will be quoted inclusive of taxes, except for €1 or €2 per person per night tourist tax payable in cash at the end.

Amsterdam is not a particularly inexpensive city to stay in.

You can find chain-style business class hotels for around, $100USD in the corporate parks around the Sloterdijk Train station (it's half way between the airport and the city center). Easy connections to Centraal Station and other locations in the centrum, but it will be a very sterile neighborhood.
Same deal with the hotels around the RAI convention center/World Trader Center between events.

http://goo.gl/maps/doZQP

http://goo.gl/maps/ZWP6V

Having said all this do your best to find a hotel in the lovely city center. Check out the RHO Hotel or Avenue Hotel. Booked way in advance you should be able to find rates that fit your budget.

Arie, you can find cheaper and good quality accommodation if you are willing to stay outside the second canal belt.

There are good cycling routes from any other area of the city into the more historical areas, that shouldn't be a problem. Actually, cycling facilities outside the canal belt are much better and riding a bike much easier than on the clogged streets within it - there will be segregated bike paths, intersections with bike-specific traffic lights, fewer pedestrians clueless about bike paths and interfering with it etc.

You won't find decent accommodation in central areas on that price range, period.

I'd look into budget business hotels in Sloterdijk, Zuidas, Amstelveen or Amstel. It is easier to get good deals booking enough in advance (since their costumers often don't book that early). They are likely to have little or no charm on themselves, but they offer what you want - a good bathroom, basic facilities and professional service.

Specifically, I'd also look into the following properties:
- Meininger Hotel (it also operates a hostel on the same place)
- Casa 400 (very big hotel, sometimes offer good deals)
- CitizenM Amsterdam (no-frills hotel with some post-modern references, it feels very 'industrial' but offers good deals for advance booking)
- BestWesten Hotel Coture (decent chain hotel near the Fashion Center, it has good deals when the exhibition center is not active)
- several hotels near Amsterdam Arerna (they have 3 or 4 chain hotels near the stadium/mall/station, bargains available often)
- QBIC Hotel (another hyper-modern architecture hotel, bargains often available)

In all the places I mentioned, you should be able to get something on the € 80 range most of the time with enough advance on your booking. All of them are easily accessible by a tram or subway line that will take you into the central areas you will want to visit most. All of them are a better bargain than some cramped claustrophobic 1* room you might found at that price range close to the major touristic areas.