Amazon offers its Prime members the Discovery Channel Dinosaur Collection on DVD
with free shipping
. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $2.98.) That's $15 off and the lowest total price we could find. This 2-disc set includes seven episodes.
Note that it will ship in six to ten days.
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.