Do I need to get a tax id number to raise money for a child's middle school trip?

I have twins who want to raise money (individually only because the school is not holding a fundraiser, parents have to organize their own) to go on a trip in the spring. My husband is self-employed and I do not want any negative implications involving donations and reporting to the i.r.s. We would like to hold a raffle and ask for prizes and dontations. I know that these businesses would want to "write off" contributions. How does this work without getting complicated? I would prefer to not go through a commercial fundraising such as candybars, giftwrap, etc. Thanks for any input.