No, not worth it. First off the repair can be difficult depending on where the leak is. Then you must have the proper equipment such as evacuation equipment. License to purchase the R-12 gas if that is what is in it. If so the bottle of refrigerant will cost you more then just a new fridge would. If you hired someone to fix it the cost again would be more then what these little fridge's cost.
Then after all that, if you fail at putting the proper charge in it, it will freeze up or burn out.
Also many small refrigerators use aluminum coils. This alone can be quiet difficult to solder if you have no experience in doing this. You would be better off selling it for scrap and putting that money into a new one.