I knew about the sticky note already (probably should've mentioned that), but the customers still get mad at me no matter what. Give them too little? Mad at me (Obviously). Give them too much? Mad at me (weird but ok). Give them exact change? MAD AT ME!!!
Ok, So let me run this scenario by you. A customer buys stuff for 17.75, they pay with a 20. I take the 20, put it in the register and give them three 1.00 coins and and one 0.25 coin. My math is correct and they should be happy, yet they still get mad. Is it possible that the bug carried over to the new version since I'm using an old save?
A good way to think about it is backwards. They paid 20: 20is the goal. They paid 17.75. So resolve the awkward coins first. Hit them with a .25 to make 18. Now, hit them with 1s until you make 20. So add 2.
Until you hit amounts greater than 30, they will always pay to the nearest divisible by 5, so you can usually just add coins, from smallest (minus pennies) to largest, until their subtotal reaches the nearest divisible by 5 number. Though this thought process did screw me over when they paid 32 on a 40...