Tomorrow I am buying a brand new 20 long with lights, so I will have a standard 20 gallon up for sale. Comes with a light, canopy is one of those glass fitted hinged lids with a handle and the light is working just needs a couple bulbs. Holds water, does not leak. will have gravel in it if you would also like the gravel. It will not be ready until the weekend at some point, as it will take a bit of time to transfer what is in it to the newer one.
Also comes with an airpump that I no longer use, an under water gravel filter, and a muselum decoration
$30
(the picture is of the tank as it currently sits)