How much money should I take to Disneyland?

So for the end of 8th grade trip my school is taking us to Disneyland. I already bought my ticket so I don't have to worry about that but I am wondering how much I should bring? I want just enough to buy food, a giant lollipop(: and a souvenir. I'm trying to keep it under $100 because the next day I'm going to the San Diego County Fair and I'm taking $100 for that. So please help b/c I'm clueless! ahaha Thanks!! <3