There are many different types of door closing mechanisms - not all are the big overhead unslghtly boxes that you seem to refer to, which are mainly for commercial or industrial uses. There are at least a couple of types that are connected to the jamb of the door, and one that is concealed inside it, and you don't need to go to a lot of expense. A lot depends on how the door is positioned, whether it opens back 90 degrees flush against a wall, etc. Any good hardware store should have a few types in stock so have a look around.
Have a look at these and you might find something like what you're looking for and it might help when you do go to a hardware store.
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