Hello,Customerand thank you for contacting Just Answer. We appreciate the opportunity to be of service to you.
Contact the manufacturer of the wheelchair and see if they can give you some idea as to its' value.
Here is a link to a Supplier of Used Medical Equiipment:
You may find the make and model there and use that as your reference or contact them to see if they can help.
Here is the link to the contacct information including phone numbers of the site I sent to you.
However if all else fails I would print out and document the ebay price and use it.