Best Buy offers Thomas & Friends: Thomas' Christmas Carol on DVD for $1.99 with free shipping. (Amazon offers it for the same price with free shipping for Prime members, however it's temporarily out of stock. It can be ordered at this price for delivery when available.) That's the lowest total price we could find by $5. It includes a sing-along music video.
Amazon offers Prime members The Americans: Season 1 on DVD for $5 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $4.98. Target has it for the same price.) That's the lowest total price we could find for this 4-disc set by $6.