If you don't mind me saying so, you'll maybe attract more interest if you give some details about usage (inclding miles covered which gives a rough idea of charge/discharge cycles) and age of the battery. If used only lightly, then a buyer needs to know how the battery has been stored.
Selling a 2nd hand battery is not easy as a buyer, or at least a knowledgeable one, is only too aware of the problems that there might be, or can arise from, a used battery of little known provenance.