My answer on Quora
Netflix pays this amount to avoid the automated letter processing for DVD return mailers. It seems quite low but there are a few reasons for this:
1- Netflix sleeves are bright red so that Mr.Postman can easily discern the product.
2- Square sleeve…again easily discernible.
3- Netflix has 58 shipping locations which reduces shipping distance.
4- Netflix utilizes Permit Reply mail where return postage is prepaid
and the postage due assessment step is not required (as opposed to
Business Reply Mail).
5- Netflix ships so many DVD that the sorting of its mailers and other mail can happen further upstream…bulk process management.