The comics were from the rich dads store. When the woman who worked there was seen cutting off the top of the front pages (in order to get the credit from the unsold items) the kid asked her what was going to happen to them. She told him that the comic book delivery guy comes to collect them.

The kids waited for the comic book guy & asked him if they could have them. He allowed them to take the comics on the promise that they don't resell them.

As for the legalities of their business. They were a pair of 10 year olds, who cares if they paid taxes?

Did you or I pay taxes on any of the many drug deals we'll have been involved with over the years? I know I didn't.