PRUITT: I got the car at Dawson's garage.
DARYL: Is the car okay?
PRUITT: Yeah, I paid for the window, that's my fault. But Dawson's going to make you pay for the tire.
BRAD: How much?
PRUITT: Fifty bucks.
So yeah, he was originally going to pay for a tire, but the money he was going to spend on the tire ended up paying for the windshield that he put a bullet through instead.
It was the “But Dawson’s going to make you pay for the tire” part that confused me: Pruitt previously said he’d pay for the tyre, so why did he then change his mind?
Maybe he didn’t have enough money on him to pay for both, but this wasn’t really explained.
Because he's now running from the law and not in the same situation he was before. He broke the window and paid for that, but it meant that the kids would now have to pay for the tire. He's not exactly in a good spot to run to the bank.