How many Euros?

I will be going to Europe for two weeks. I am going on a cruise ship and all the meals and drinks (excluding alcoholic drinks) are included on the cruise). I will be visiting 10 different ports (Spain, France, Italy, Gibraltar) in these two weeks. I will not be in each city for more than 12 hours.
Basically I want to know, how much money will be a good amount to take with as spending money? For example gifts for family and friends, entrance fees to places like museums, trinkets, a snack sometime, etc? I have no idea how much things cost in Europe!

Thanks for the help!

For entrance fees and snacks I would plan on roughly 20 EUR for every day and person that you are in port. For souveniers I don't know, it depends upon your taste. I think that with 10 ports 500 EUR would be a safe amount to plan on, this will allow you to shell out for that 250 EUR Italian designer handbag if you are so inclined.