The thug's just a boy once my money in the bags
I think this means that once Yoni buys all of the drugs that a thug has on him, (putting all his money in the bag) there’s no difference between the former “thug” and a boy.
I also think that this is used to show how once you remove all the bad things from something with a negative connotation you’ll find that it isn’t bad at all, and that everyone is innocent deep down.
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