Disney funding?

I'm going to Disneyland Paris soon, everything is paid for - coach, ferry, hotel, park entry & we get breakfast included.
How much money do you think I will need for food/drink? I intend to take a bit extra to buy myself something nice, but just asking about how much I should take for food/drink.
I only have to pay for myself, & we will only have a day & a half in the parks.