I've been looking everywhere for it but I don't see a shop selling one or in any of the screens that I've explored 

(Before sending this I gave it a couple days of searching and now the task has changed to "Get some help from someone" idk why but ok, it's the only green objective currently) 

You can buy it in a Shop, i dont remember which one, but it is one of the Shops you can visit right from the start so it should be not that hard to find.

Newsstand at the Busstop