Replacing transmission oil

Hi there!

I'm planning to replace the transmission oil of my BMW 730d E65.

Here is the pic:

Attachment 1202637


I've searched this code on eBay and I found different prices:
From 4$/Liter to 30$/Liter. What's the difference between these oils?
Here is the products:
http://ift.tt/1DS5D4C

http://ift.tt/1DS5D4E

It is worth to buy the cheapest or not?

Attached Images