As a garage sale host, you are going to come in contact with a lot of people over the course of your day. You're going to see them walk away with your things, and you're going to take their money. You're going to have to deal with grumpy people, peppy people, and everyone in between -- a stressful day, to be sure. Trusting your customers is something that will really reduce your stress levels and help you stay sane on garage sale weekend. But is it a good idea?
Yes. There is no need to be paranoid. Yes, the news may have announcements about how people stole from this garage sale or took counterfeit money to that sale, but recall that those are the bad incidents, and realize that in the grand scheme of things, the number of scammed hosts compared to the number of successful sales is incredibly small. The news doesn't report on the happy yard sales! So no, you don't need to stress out that every single customer you deal with is going to cheat you.
Staking out your tables is not necessary. You certainly want to keep an eye on things, if for no better reason than children tend to hang on to things without realizing that it's stealing; we're not saying you should stop being watchful. But you don't need to stalk through your sale, casting a wary eye on every movement your shoppers make. Stay seated at the sales table or browse casually to say hi to your customers.
Do keep valuable items with you, but let people browse. Chances are, if you're selling it, you want to get rid of it. That doesn't mean you only want to get $1 for that stained glass fixture, and yes, you'll want to keep the box near you so the chances of someone breaking it or taking it away without you noticing are lessened. But let people browse! The point of a garage sale is to have customers perusing your secondhand merchandise, so you should make sure they're free to do just that.
What about counterfeit money? If you're really concerned about counterfeit money, you can take one of these precautions, none of which will force you to stress over every customer you take money from.
Make it a policy not to take bills higher than $10. Rarely is anything less than $20 counterfeit, so you won't need to stress about checking each bill.
Keep a marker with you and discreetly and routinely mark the bills. If you do find something, you can report it to the police in good time.
Make it a policy to check every bill, so you aren't singling anyone out.
Again, above all, just trust your customers! People are normally civil and wholesome in their dealings with others, particularly in a garage sale environment, so there's no need to mistrust everyone.