Thus, I have devised a couple of rules for small tips:
1. For restaurant bills, or those of any service business where tipping is customary, less than $3.37, leave $.50. In most instances, the change received upon paying the bill will exceed this minimum payment; in the event it does not, break a bill, or just keep a quarter or two handy.
2. For bills between $3.36 and $6.71, leave $1.
3. For any bill over $6.70, figure the tip and leave the amount to the nearest $.50 (the instances when this results in tips slightly greater than 15% will balance those instances resulting in tips slightly less than 15%).