I just need a money detector first

Many times, I’ve got an offer at work to be a cashier but I said ‘no’ to it. I am not confident with counting coins and I am afraid of receiving fake bills. I can remember when I shopped at the local store in our place once then I brought lots of coins, I put it in front of the cashier and I let the cashier count it for me. Ha-ha, I am afraid of karma. Although, it is nice to know how to operate a cash register machine but maybe later when I have my own money counterfeit detector I will have to accept the offer. Right now, I am looking for a good money detector and soon I will buy one so that I’ll be ready to be trained as a cashier.