Hello, Kimluk –
As eNate points out, you don't share much info in terms of where you are, BEV / REX, or options. Location makes a difference. Looking at autotrader.com, if you're in Tulsa, OK there are zero used 2017 i3s available. In Dallas, TX there are two. In San Francisco, CA there are 57!
In general, the last thing your dealer wants is your i3 lease return. As soon as they get it from you they're likely going to ship it off to auction.
Any chance you know someone in your area with a car dealer license? If so, ask if they have a Manheim membership and would do a search to see what your config is going for at auction.
With the limited details in your post, here's a retail i3 at Peter Pan in San Francisco, CA... a 2017 BEV with 30.7K miles, asking $21,998:
https://www.autotrader.com/cars-for-sale/vehicledetails.xhtml?listingId=527146260
This car will probably sell at auction between $12,500 and $14,500.
If you can get real auction data available for a car that compares to yours, you may be able to negotiate a discount with your dealer. Before your lease is up, schedule a meeting with your dealer's Lease-End specialist and share with them comparable auction sales.
BMW doesn't allow a dealer much freedom on a lease return (you're not going to get your car for $14K!) but you should be able to get a buyout for less than the advertised retail price.