I apologize if someone already suggested this earlier on this board, but I don't have the time (read: I'm too frakkin' lazy) to read all the posts.
My idea has always been to get rid of the penny and always round up to the nearest nickel. (if the total ends up divisible by 5, there is no rounded amount). The rounded amount does not go to the business, rather it is a additional sales tax. You take those extra cents, which will build up to a big number, and put it towards schools, roads, public transportation, anything that people complain about now not having enough funds.
In each individual purchase, you are talking a maximum of 4 cents extra. If the average person makes 1 purchase a day, that is a maximum of a reasonable 15 bucks a year (where as the average, 2 cents extra, would be 7 bucks a year). And if you look nationally, 300 million people (not all of whom make purchases, but others who make more purchases make up the difference) paying an average of 2 cents a purchase, an average of 1 purchase a day, amounts to over 2 billion dollars. Wanna get rid of the nickel too, and round up to the nearest dime? Maximum of 33 bucks a year per person, average of 17 bucks a year per person, and almost 5 billion dollars nationally on average. I don't know, seems to be OK to me
There are 10 kinds of people in this world: those who understand binary, and those who don't.