Usually Jason wears only his tanktop and a thong when going shopping. It's the apocalypse, clothes are probably the last thing on anyone's mind right now. Player (or Jack as I'm going to start calling them) is a bit surprised by his outfit though, maybe Jason will convince him to start wearing less clothes.
Decided to make some fun edits of it too, the tanktop is really the only thing that covers the most of him, because he might be a bit big in certain areas to even wear any underwear.