The whole question of what is a "Fair" price comes up at least once a month on CGN. It usually is prompted by someone asking twice as much for an item that it sold for two years ago (while it was available - read $600 for an SKS-D ), asking more for a used gun than it costs new, or asking more than an identical item can be had for in the US, or even somewhere else in Canada.
I've seen whackos go so far as to suggest that sellers should be required to abide by some sort of CGN price controls that would make communists weak in the knees, after all we're all brothers, right?
Of course unless it's a life essential and under exceptional circumstances (like selling water after a disaster), "fair" is whatever the buyer and seller agree to.
Do some research and decide for yourself. If afterwards you experience buyer remorse, suck it up and learn for next time.