How much would a tattoo like this cost and how long would it take to complete?

A friend of mine is pretty adamant on getting a tattoo of a snake wrapping around her body from her foot to her lower back. After the snake ends, a phoenix coming out of the snake covers the rest of her back. This is a pretty big tattoo. How much would such a tattoo cost and how long would it take? How painful would you say it would be?