Either way, it’s a great deal. I prefer to pay the $99 up front as I don’t like to deal with monthly payments when I can help it.
Make sure you take advantage of all the the Amazon Prime features like streaming music, TV shows and movies on demand, and unlimited storage for photos.
I agree about the discount, if you can afford it, its better to pay a year up front.
But if your budget doesn’t allow it, paying over time is great too and there’s no commitment to stay though Amazon is betting long-time customers will stay with them because of the free shipping and benefits only Prime members get.