Jobs!
Thanks for the input, to be honest I'm a bit loathed to have to turn up to each class with a bag of sweets and be the candy dispenser. The hot choco and ramyeon took students a while to get (maybe once a semester, if that), so it worked well as an incentive to maintain their interest. It doesn't look like there's a budget for sweets either :(
Thanks for the input, classdojo is very useful but I tend to use it only for classes I see more than once a week. Yeah it looks like I'll have to suck it up and dive into my bank account if I want to offer a variety of rewards. Cheers for the suggestions