When you run out of money and try to buy a jet ski it obviously doesn't buy one.
BUT, the game keeps buying the jet ski even though you have no money.
When selling any item and it gives you enough money back for a jetski it buys one.... In spawn....
Im including a video here as well because that might just be a whole lot easier to understand. I might be loud in the video though so watch out :P.
(Notice bottem right that it keeps trying to buy a jet ski)
(There is also a jetski flying away in the distance coming from me too, meaning it bought multiple)