Newbury Comics via Amazon offers its Prime members
Pirates of the Caribbean: At World's End Special Edition for DVD for $5.99 with free shipping.
(Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $2.98. Or, Comp-U-Plus
charges the same.) That's the lowest total price we could find by $25. This 2-disc set includes a short film, outtakes, interviews, and more.
Amazon Prime membership is $79 per year; however, Prime is free for college students for six months, and free for parents and caregivers for three months.
Update: Of note, amazingwildcat via Amazon has it for $5.98 with free shipping for Prime members.