Now you are worried about inflation?
The price doesn't go up on anything on paper. A stamp cost 42 cents. If you buy one it would cost 40 cents. If you buy ten it would cost $4.20 if you bought 53 it would be $22.25 instead of $22.26. I could see how an item that would be purchased in bulk such as stamps would go to 43 cents so it wouldn't be cheaper to buy them 1 at a time but it doesn't have to jump a nickle.
If gas is $2.99 a gallon and you buy 10 gallons then the total would round up from $22.99 to $30.00 or it would cost the consumer a whole tenth of a cent per gallon.
I see what you are saying about businesses trying to use it to increase profit but if they wanted to raise prices now nothing is stopping them. Competition determines the ultimate price of an item.
It really isn't that important to me. I already round all my prices off to the nearest $5 and anytime you multiply a number (tax) by 5 it comes out rounded to the nearest nickel anyway. It would just save the country time, money and natural resources as well as the energy used to mine and produce pennies.
Just saying if we wanted to do it then it wouldn't be difficult at all.