Most stations where i am (Florida, USA) have a convenience store + car wash built into the side of the store. air pumps and vacuums (for vacuuming dirt out of your car) are also extremely common.
EDIT: Also vending machines is pretty common out-side, and depending on year that apocalypse happened, about 10+ years ago every station had payphones (less and less now do), or if it’s based on present day tech, many gas stations i see have new stuff like redboxes and all out-side. but i doubt pay phones or red boxes would have much relevance in Cata, vending machines may be useful though :)… IE Bash vending machine to pieces and recover some soda/beverages and coins!!, some vending machines may drop snack/junk food instead like potato chips, etc.