Teach your students to count coins! Hook your Makey Makey up to the computer. Attach the: Up Arrow to a Quarter Right Arrow to a Dime Left Arrow to a Nickel Down Arrow to a Penny Have the students click the items add to their purchase, then click checkout to pay. Student then need to tap enough coins to count up to the correct amount of money.
I downloaded the cash register from pixabay (https://pixabay.com/en/cash-register-till-register-576769/) I got this idea from a You Tube video made by "Julie Smith: The Techie Teacher" called Academic Ways to Use a Makey-Makey in the Elementary Classroom.