1/2 gallon is perfectly do-able. I've got no-tech tanks running from a 1"x1"x2.5" acrylic box up to a 3g planted vase--plenty of .5-1g tanks in between. Various snails, ghost shrimp and cherry culls are the range of inhabitants. Though the 3g also has some endler/guppy hybrids.
This one-in a standard highball-- sits at eye level by my computer: sand, six types of plants and MTS. Weekly 50% wc, indirect sunlight supplemented by a full spectrum bulb reading lamp nearby.