I'm planning to go with a $1/mile rate, hopefully it'll keep me motivated to stick to my 3 mile weekday maintenance runs. I showed my hubby the jar and explained my plan. He's excited for it, but I don't think he'll be participating, since he regularly averages 100+ miles/month! He'd have an awesome stash at the end, though!
Here are some pictures (plus my Disneyland 1/2 race shirt turned tote bag in the background).
Would you try a tip jar? Do you have any other motivational tricks?