I'm probably the last to know this, but just in case....
Amazon Student gets you Amazon Prime free for 6 months (without the instant videos), but then for $39 a year you can get the full Prime. You have to have a student email address (ending in .edu), but this sounds like a great deal! I'll have college kids for another 10 years.
We ordered books from Amazon for my college son this past year and will do that more often if we get this.
Also,
Amazon Mom is 3 months of the Prime shipping.
So, does anyone have Amazon Prime for instant videos and do you use it?