There's no way to tell thats a bloodred stripe from that picture. To me, without seeing the eyes, it could be an Amel stripe, or a Normal stripe, even a Hypo stripe with some nice cubing. Its hard to tell.
The price sorta depends. Is it male or female? Are they buying it as a pet or for breeding? Judging from the pics, it looks like the snake is pretty well established, if not an adult. If that were the case, I would ask at least $80-$100. As an established adult, it's worth at least that without even considering the genetics.