The definative list of fighters who truly seem like they would box for no money: 1) James Toney 2) James Toney 3) James Toney 4) Ricardo Mayorga 5) James Toney 6) James Toney 7) James Toney 8) James Toney 9) James Toney 10) Did i mention James toney?
Nobody. You could say there's boxers who care less about money than achievement and legacy, but it doesn't mean they don't care about money at all, just that they may except less than others. No professional boxer is going to step into the ring with their life in danger everytime they do so and fight for nothing.
jmm comes to mind when he fought chris john for just 30k. peace jmm fans. kidding aside, luisito espinosa didn't get paid of his promised purse up until now when he fought carlos rios of argentina for the WBC 126 title more than 10 years ago. it's more like of a scam where the promoter didn't release the purse to him.
Historicaly there have been examples of fighters who made a net loss on their purses after deductions. Primo Carnera made a net loss, so esentialy he was paying his handlers to fight. A lot of George Godfreys purses never materialised and he waqs inumerate so he had no way of knowing if he was paid corectly.