Amazon has Transformers One (4K Ultra HD + Blu-ray + Digital) for $14.43. Shipping is free with Prime or on $35+ orders.

Thanks to Deal Hunter phoinix for finding this deal.

Note: Please note the combination of "4K UHD, Blu-ray, & Digital Copy" may vary. Not all releases will include all three formats. If the film comes with a digital copy, the code might be expired. Please check individual listings carefully.