As Mr Big said to James Bond "Names is for tombstones, baby."
I am guessing that there is a seed out there that would produce a plant JUST like the one you smoked. Also if it is someone's own little cross yes the only way is to grow a clone of it. If it is a local thing then there is a good chance that the clipping you get wont be the same as the one you smoked.
when it comes to buying and winning a negation there are 2 types of people that win. The patient, and the well informed. you are trying to go the latter root. Since you dont know the plant lineage, genetics or authenticity. My suggestion is to offer the seller 10-20% over the price of a single seed from attitude's pick and mix section that has similar qualities to that of the plant you are looking to get and tell them why you came to that price. hell say I can get dutch seeds for X price. Negotiate from there but I would absolutely never go above twice the price of a similar seed as at that point pop the seed hell buy 2 of them and pop them both. the only reason to spend an ass load for a clone is if; a the seller is reputable, has good product that you purchased in the past, or is the only one who has what you need/ really want. If not play hard ball.