The honor system is true. I used to go buy gum and candy (and cigarettes for my mom), and only sign an IOU slip. They sent my dad a bill at the end of the month.
The honor system is used in the small town I live in here in Maine (roughly 2,000).
A farm stand in late summer down the road has a metal box with a slot attached to a long table with a tarp for a roof.
You buy the tomatoes and cucumbers and other produce you want, and put the correct amount in a slot in the metal box.
The small tomatoes are in small clear plastic glasses with a price attached, usually 50 cents per “glass.” The bigger tomatoes have price stickers on them. Cukes are one price no matter the size.
Another home further down the road has an unmanned produce stand just off the driveway of a home. Off the driveway is a half-shed loaded with all kinds of produce, and they even have a small refrigerator built into the half-shed which is open in the front and has a wooden roof.
There is a scale for weighing the tomatoes, lettuce, cukes, etc. that you want, and plenty of price lists. There is a tan plastic coffee can with a green lid; it’s load with change and paper money, and that’s where you pay and make change. There are vegetable gardens all around the house and a large greenhouse behind the home.
This time of the year, there are a number of roadside stands with people selling hand-made Christmas wreaths on the honor system, made with local balsam tips.