Pretty sure it’s a scam…but how does it work?

So a few times a year someone always knocks on my door and basically says “I made some mistakes in life. You can buy X and I get y% commission. It helps me and helps the cause” and has this stupid little packet that more or less seems like it’s just to help “prove it’s real”.

In this most recent example, the guy was selling book donations. He said he got a small cut and books went to some charity. He said he got in trouble for selling weed and either this was the only job he could get or he had to work X hours for some type of probation thing. Went on and on about how they take Venmo, square, cash, etc. explained how to write the check exactly. Had a little packet with all the “info” as well as his picture seemingly trying to make it look official.

Of course I said no thanks good luck, but how does this work? Is someone just foolish enough to pay the Venmo or wrote a check and assume they’ll get books or proof of the donation? Am I totally off and this is some type of MLM? Had the guy been swindled?