As a condo dweller, I'm without a garage, basement, or much storage space. I most certainly don't have room to keep paint cans around the house. I read somewhere about paint savers made by Tupperware or Rubbermaid, but the last thing I wanted was to spend $15 on a plastic storage container. One day, after pulling a Classico sauce jar out of the dishwater, I realized that I should be holding onto them instead of adding them to the recycling. I started saving the clean jars and have been slowly transferring my leftover paint to them.
With the paint in jars in the pantry, they're more accessible than paint cans stashed in the back of a closet. I don't think twice about popping open a jar when a wall needs a little touch up. Some plastic wrap between the lid and the jar prevents dried paint from collecting in the grooves.