erm...I dont know if im just a big spender compared to you guys, but we were going to do this over easter but have had to cancel as we cannot afford the spending money. We were going to do 10 cities in 15 days, having a night out in each city. Basically although we had bought the pass, you still have to pay extra for booking fees and overnight trains, I would leave about £100 for that alone. + at least £20 a day for food, your cost of nights out, hostels, taxis, getting to your first destination (passes are not valid in your own country), any activities you want to do while your there, sightseeing, etc. We basically worked out that for our 15 day trip we were going to need about £1500 spending money. Obviously eastern europe will cheaper but places like paris are mega expensive and unless your not planning on going out much at a night time, I think you will need to set aside at least £60 a day.