Lodging for Solo Trip in Amsterdam

I stayed at the Amistad Hotel, Kerkstraat 42, http://www.amistad.nl. It's a "gay hotel" but friendly to all. It actually meets all of your requirements! 1. Price. My room with private bath was €115 per night, but there are rooms with shared baths for less. 2. Convenient neighborhood. It's right near the Leidseplein, but on a quiet side street. Lots of restaurants, stores, etc are nearby. 3. Near a tram line. Three lines run on the main street a few doors from the hotel. 4. Free WiFi. Not only is that in all rooms, but there is also a computer (running Linux) in each room. 5. Self service laundry. One block away, just across the main street with the tramlines. 6. Quiet. I don't remember any particular problems with noise. 7. Does not get a party crowd. This was a particular concern of mine in Amsterdam as well, and this hotel was fine on that score. The only possible problems: 1. They have a 4 night minimum over weekends - all year round.
2. They do not have an elevator, and the stairs (like in all of Holland) are steep. I was on the 4th floor (by US count); OK for me, but not for anyone with any leg problems. And one more thing: my room was much plainer than the one shown on the website. It was fine otherwise. I do wish you good luck. As you're finding, rooms in Amsterdam are not particularly good value for money, and the same few places with few rooms are in all the guidebooks (including RS), so they get booked fast.

Check out the hotel Bema just outside the museum district right on the tram line. Clean, very nice breakfast and pretty reasonable.
No idea what the cost is today, however in May 2011 a room for 3 with breakfast and private bath was 120E

We really like the Hotel Fita and the Hotel Weichmann in Amsterdam. The Wiechmann probably has the best location in Amsterdam... right on the Prinsengrecht. It has a lot of history and a lot of stairs, but they are very doable...not straight up. I think some of the nicer rooms on the canal with a view may have a room AC but maybe not. They have all kinds of room. In the Museum.. Vondel park area is the Hotel Fita.... wonderful and a wonderful breakfast. I think they still do your laundry free. Both have a laid back clientele and have single rooms. They fill up really really fast.

Check out the Eelhouse B&B in the Jordaan. We haven't stayed there yet but have reservations for November. They have a great breakfast, and fill up your mini fridge every day (free of charge) with water, juice, and wine! Their prices are from 90-120 euro depending on time of year.

The Hotel Van Onna is another option near the Jordaan.

Thank you all for the recommendations. A number of them are, unfortunately, already booked for some of the dates I am looking for. If you have any other lodging recommendations you have enjoyed, please feel free to pass them along!

I stayed at the Hotel Orlando (more like a B&B) a few years ago
http://www.tripadvisor.com/Hotel_Review-g188590-d197798-Reviews-Hotel_Orlando-Amsterdam_North_Holland_Province.html Really enjoyed it. But my stay was a while ago so I can't comment on anything recent, I'd read the reviews to see if it's still nice.

Do a Google search for Hampshire Hotel Beethoven. We have used it twice. It may fit into your plans.

Thank you Debra and Monte.

If you haven't found a place yet, you might try Booking.com. Your price per night is reasonable ($155 dollars today) and you shouldn't need to share a bathroom down the hall for that. You can switch the currency to Euros if you want. You can use the down box to select 1 adult and there are lots of filters you can apply (price range, district, Wi-Fi, non-smoking, etc.). With your specific dates, you should be able to pinpoint some targets. I always sort them by Review Score, then scan the prices. You can go through Booking.com or contact the place directly. They list hotels, apartments, B&Bs and other types of lodging. I wouldn't avoid looking at the apartments because going through Booking.com, there may be no security deposit or cleaning fees. The details on anything you click will talk about that. Most of all, I love the pictures showing the rooms and more about the place. I tested this for only one night (May 7) and there were lots of very cute options within your budget, some even with breakfast included.

Vondelpark hostel isn't too bad. It's very close to a tram line and the museums. For going solo, a hostel is usually the best deal. I'd expect to share a room with other travelers. The room we stayed in there had six beds and a connected bathroom (for just our room).

I stayed solo at Hotel Brouwer http://www.hotelbrouwer.nl/hoteleng.html - great location, lovely staff, nice breakfast. The rooms are indeed very small, but it was clean and cozy. They book fast, so email your request right away.