Boris is a lazy fairy. He sometimes comes for the tooth a day or two late, and he doesn't put much effort into the payment. He might leave a wrinkled fast food coupon, a single dollar, or a few coins. He sometimes even forgets to take the tooth with him.
Lizzie is a very thoughtful fairy. It sometimes takes a few days to cash in the tooth when she's on duty because she shops for the perfect gift instead of leaving money. It's worth waiting for her because she leaves items like a new outfit, bracelet, book, or toy. She's even been known to leave a note indicating that she made arrangements with the child's parents to allow them to skip a chore for a week in exchange for their tooth.
Then there's Phoebe. She's a very wealthy fairy and very rarely takes a shift. She doesn't need the income, but occasionally she gets bored and a lucky child scores. She leaves twenty dollar bills under pillows - for just one tooth! She is only interested in teeth in pristine condition, though. Proper brushing and flossing with raise the likelihood of a visit from Phoebe!
Whatever the origins of your family's tooth fairy story, you can always use it as a motivation tool to instill good dental care habits. Children should brush for two minutes twice a day. They should also floss daily. Remind your child of the tooth fairy's expectations when they grumble about brushing and flossing. They won't want to disappoint the tooth fairy - especially if there's a chance of attracting a rich fairy like Phoebe with well cared for chompers.