Two years now, everytime I want to cancel my eBay Plus, it offered me $30 voucher to shop anything if I don't cancel.
Thus don't just let it extend your subscription, try to cancel it before renewal, then see the voucher offered to you, accept the voucher, then continue with the renewal.
Good luck
be aware that the voucher often has a short expiry date and usually has a min purchase amount to use it.