If all goes as planned, you're going to be handling a decent amount of cash. Plan ahead and make sure you've got plenty of singles and change to hand out, but also make sure to keep the money you've earned safe, so when you feel like you've got a bit too much in the box, run it in to the house for safekeeping. You've probably got a smart phone, so you've already got the calculator covered and having a cashbox or pocketed apron can make your money management so much easier!
Check these must-haves off your list and reuse them year after year.
In today's Internet-connected world, there's no reason you can't easily accept credit cards at your garage sale. All you need is your smart phone, then go sign up for Square to get a free card reader. It's quick to sign up, simple to use, and you'll find that big-ticket items will go faster and people tend to spend more when they can put it on plastic.