As mentioned previously, any pet store is going to have higher prices to incorporate their margins, and make a profit. I think for a perfectly healthy, guaranteed female of breeding weight and age 300$ might be verging just on the edge of too high. The eye deformity should absolutely drive that price down significantly.

I would offer 200$ and not go much higher than 225$. Bring cash and have it ready. I have found that people generally have a hard time walking away from a stack of $20s ready to go