thank you everyone for the help! The individual marble idea is definitely out since I have this vision of hundreds of marbles hitting my floor as they're knocked over daily.
Instead I've decided to go with a class marble
jar for group rewards.
For individual rewards I plan on creating a paper chain for each student, adding a link for each good deed with the reason for reward written on the paper. This not only serves as a colorful display in the class but also a great scrapbook of good things at the end of the year for parents to see.
As far as discipline. . . it would obviously be too mean to
take away the paper links that they had earned, so we're doing a '3 strikes and you're out' thing. I'll laminate some baseballs and magnetically stick them to the front of the desk for bad behavior. Each one will have a consequence and if you get 3 you have to leave the classroom.
sorry I wrote so much. Do these sound like age appropriate ideas? thanks!!!