Your looking at around 40euro a night for a hotel, and that is most basic. When you get into the train station in Amsterdam, you'll find a VVV outside. It's a tourist office and they have an up to date list of all the available hotels on computer. Once you add up the cost of drinks, smoking material, food, taxis and night clubs entrance fees you are looking at off the top of my head 50-100 euro per day. I used to go there and live on Maoz falafels for 4 days, get stoned and that and come back 5 days later about 300-400 UK pounds out of pocket. Amsterdam has become a very expensive city since the euro came in.