Do we have shots taken with A* or M* lenses?

I want to be double sure before I buy it.

I am also interested to know why someone sell them when they are so good?
I just want to know ins and out of this lens, as the price is too much for me.
I want atleast 80% in image quality to the best available under the Sun but want to pay 50%.
I do not need autofocus.
What is the weight of this lens?

I want know how much this lens should reasonably be bought from anybody if the lens is in very good condition without any mark or scratch or fungus on the lens elements but with minor mark on say lens hood.

I am new in UK, and was quick to understand that UK market is costly compared to say US. But still, hobby does not listen to reasons, so I want to buy one 300 A star. F star is beyond my dreams.

Thanks for your inputs.