or maybe you have to mail the coupon in. I remember when take along coupling switch from magnetic to the plastic hooks, you can get one or two adaptors through the mail while supply lasts.
My Trackmaster/Tomy/Plarail Photo Gallery Page (over 600+ photos and still under construction)
https://www.flickr.com/photos/183311600@N03/
https://www.flickr.com/photos/183311600@N03/