It's dirt cheap, I took a starting deal package which costs me only 3 euros per month for 6 months, and then onwards it costs 6 euros. It's basically 1/4 the price of my Netflix at present. And they have other awesome, original content as well. American Gods and The Grand Tour alone are easily worth it, then there are other great shows as well, and lots of documentaries you won't find elsewhere.
Here I thought The Tick was the only original thing worth watching on Prime. I'll try to remember to check this one out when I get caught up on Hulu.