If you are looking for cards (as an example), you go to CVS, Walmart, etc. and find what you are looking for. In Spain, if you try to go to a pharmacy to look for cards or other similar things, you’ll be out of luck. The stores here are direct and to the point in terms of what they sell. If you are in need of medicine (for allergies, etc.), you go to a pharmacy. For food, you go to a grocery store. Of course, there are stores here that are sort of like Walmart, where you can buy it all. El Corte Ingles is one of these department stores that is just that. However, stores like these are few and far between.
Another thing, “24 hour” stores here, do not exist. The latest store here (El Corte Ingles is again an example) closes at around 2am, but it depends on the time of year. You also cannot just buy things at anytime during the day when you want. During the afternoon (between 2pm and 5pm or so), siesta takes place, so many places are closed during this time.