I used a generic motor which you can find fairly cheap on line or in the Maker's Beginner Kit (CZ002). As for the the rest, I just used some boults from a pack I bought at Walmart, I think they were like $4-$5 for the whole pack. 

you'll need to find some way to seal the two halves with a water resistant sealant if you don't want any leaks. just make sure to line every thing up properly so that the motor can spin freely if you decide to glue them as you wont be able to change it.