I don't really think they're the sort of thing people get rid of TBH, I've had mine coming on for 8 years now & once it dies I will get another one. I know they're expensive but I think they work out cheaper. if you don't get one as a trade, try the apple refurb store, think they are about 30% less than a new one & some say they are more reliable.
I took my iPhone 4s back a few times because of poor battery performance & the refurbished one I got is much better.
But you never know someone may have one, they do come up on eBay, so good luck
