I already own a large normal female about 4 yrs old. This week I may be buying my 1st morph ball, an semi-adult male pastel about 2 ft. in length. I would be buying it from a private party not a breeder. They say the snake is an adult male pastel about 2 feet in length, and they have no paperwork for the snake. What is a fair price to offer them for this snake?