If you meant to type 264 Winchester Magnum, wholesale on new brass is about .56 each. Available from most supply houses.
If you've got 284 Winchester brass, it is now a seasonal production piece - last wholesale price when available was .55 each. The usual suspects don't show current inventory.
If somebody is "needing" correctly headstamped 284 Winchester brass, and you've got some - it'll bring a slight (or better) premium.
24HourCampfire, Accuratereloading, etc. would be the websites I'd be trying to peddle it on if I had some.