I would say that you could find restaurants with meals around 10 euro, drinks cost extra.
Hotels you could find around 100 euro, maybe a bed & breakfast is also an option. There are also apartments were you can cook your own meal. That's maybe a good option if you want to make your own breakfast/lunch.
The tourist information can give you a lot of suggestions. Make sure you google for reviews. The experience from other travelers can help you make your choice. For example you can rent an apartment for 40 euro a person a night: http://www.iamsterdam.com/en/placestogo/aaa-shortstay-amsterdam-apartments/85eee59a-8267-4b46-b2b8-0daa723aa3ad
Look for more info on the tourist information site under accommodation.
The tourist information has a very good site:
http://www.iamsterdam.com/en/visiting/touristinformation/contactatcb
Travel books like Lonely planet or the Rough guide offer a lot of good suggestions, maps, places to go etc. Maybe your library has one. They have also an internet site with limited information:
http://www.lonelyplanet.com/the-netherlands/amsterdam
http://www.roughguides.com/travel/europe/netherlands/amsterdam.aspx
http://homepages.cwi.nl/~steven/amsterdam.html
In Amsterdam you can eat from cheap to expensive. I found a site with restaurants that serve meals around € 10. The drinks will make your bill more expensive. There is also a list with pizza restaurants. Most pizza restaurants sell also cheap pizza's and most of them deliver pizza's.
http://www.cheapinamsterdam.com/
Hotels have often internet deals. Compare also the reviews, some hotels are cheap but are maybe noisy or dirty.
Here some sites you could visit to find a good deal.
http://www.hotels.nl/Amsterdam/?gclid=CNmL3frByasCFQGFDgodwxWt1w
http://www.booking.com/city/nl/amsterdam.html?selected_currency=hotel_currency&aid=303947&label=amsterdam-1lvczZZ4vOwZ5SD6y2KR5QS4024455559&sid=71f74578e062a8694c2c1b2c3d130eb3&lang=en-us
http://en.worldhotelsonline.org/City/Amsterdam.htm