A new 10g runs anywhere from $15-$20. I think a used one will probably sell for around $10-$15. With a heater, air pump/stone, substrate, décor, plants, and 7 guppies, I would sell it for around $30-$40, if its all up and running and if its established. (If you where to buy a new filter for it and then sell it, I would post it for however much the filter was and a little bit more. (Example: Original post: $35, new filter cost you $15, new post price: $55, see?)
People will pay a lot for a tank that is up and running, so they don't have or do any work. Good luck.
People will pay a lot for a tank that is up and running, so they don't have or do any work. Good luck.