iPad Mini vs. iPad Mini 2

Hey guys. I need a book on ibooks but have no apple device to view it on. I'm picking up one of these devices used on the cheap and was just wondering which would be the better buy.

I can get an iPad Mini for around $70-$80, while i can get an iPad Mini 2 for around $130. I was wondering if the extra $50 would be significant. I don't plan on doing much with it besides watching videos or reading iBooks.

Any and all help is immensely appreciated, i'm honestly so bad at deciding these types of things.