Amazon offers the Veho 360° Photography and Timelapse Accessory for iPhones / Cameras, model no. VCC-100-XL, for $9.99 with free shipping. (Non-members can spend $49 to bag free shipping; otherwise, it adds $5.14.) That's the lowest total price we could find by $11. It features the ability to take 90°, 180°, 270°, or 360° timelapse and panoramic photos and supports cameras that weigh up to 750 grams.
Note that it's expected to ship in two to four weeks.