MiniInTheBox offers the LED Fidget Spinner Case for iPhone in several colors (Blue pictured) for $5 with free shipping. That's $5 off list and the lowest price we could find. It's available in sizes to fit the iPhone 7 or 7 Plus, and the iPhone 6/6s or 6 Plus. The spinner is removable.
Note: This item ships from China and may take two to five weeks to arrive. Uncheck "Add Shipping Insurance to your order" during checkout to remove the 49-cent fee.