The middle option they are discussing is between never buying anything you don’t currently have the money for (what the parent commenter claimed), and buying mo

The middle option they are discussing is between never buying anything you don’t currently have the money for (what the parent commenter claimed), and buying more than you will be able to afford by the time the payment is due. You can pay your rent bill on August 1st, even if you don’t have the money for it until your paycheck on the 12th, and then once you get your paycheck, you can allocate the money appropriately so that you can pay off the bill at the end of the month worry-free.