Benford's law is about the first digit of the number, it has nothing to do with the current problem. The pennies are the two last digits. However, IMO the assu

Benford's law is about the first digit of the number, it has nothing to do with the current problem. The pennies are the two last digits. However, IMO the assumption you quoted is indeed false but due to other reason: In real life, prices are not uniformly distributed because usually they are rounded to multiple of 5 cents or commonly they are .99 or .89 or s.th. like that. I am wondering what happens if we put non-uniform prior on the probability of the pennies. Another flaw in this research is forgeting that we often are getting change back. So maybe problem is to find combination not only to give exactly money, but giving and receiving change back. For example: Using 1,5,10,20,50 you can make exact 4c only by 1,1,1,1, (4 coins). But getting change you can do 5, -1 (2 coins).