I remember those! Quite the fad when I was in 5th grade, well over 50 years ago. I think kids just want to buy and sell stuff, and it’s more fun if the teachers disapprove.
I was doing an experiment, and needed Jello gelatin to thicken up the water.
It worked fine so I bought a whole bunch more. The stuff didn’t work. So I increased my mixture and STILL no good. Seems that the cheap stuff I bought on sale was cheap for a reason - it was KOOLAID! (Right next to the jello, similar package - what an idiot!).
But, maybe I can cut it with 10 pounds of sugar and I can push it at the school down the road. (I wanted to dump the boxes off on the trick-or-treaters, but my wife wouldn’t let me!)