Amazon offers Prime members 28 Weeks Later on Blu-ray Disc
with free shipping
. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $2.98.) That's the lowest total price we could find by $5, outside of the mention below.
Best Buy offers it for the same price, however sales tax is charged in more locations.
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.