That depends on what it is you are planning to do. You are the only one who can decide what to spend. Things to take into consideration are; accommodations, meals, attractions/shows, tips, transportation, and of course gambling.
One tourist needs nothing (even a cent!), if the host covers all costs. If the tourist is on his own account of exoenses (shelter, food, transport, amusement, pocket money etc) cheaply by 20 Euro by...