There’s a difference between scanning the different headlines within to see if there’s anything that grabs your interest and reading full articles. If you’re reading a full article in the shop I’d expect the paper to then be paid for so you can take it home and read the rest. As you have suggested yourself a little later…
There’s a difference between sense checking if it’s what you’re interested in and consuming the content. If it’s the later in my mind you should pay for it.