>>4197090So check the "sold" section by your search request to see what is the minimum of the price you can buy it for.
I usually buy lenses in US and DE stores, just only ones I had a bad deal buying lens with not smooth focusing, but it could be fixed very easy so it is not a big deal, just additional 20 euros I need to spend for this.
So it mostly depends where are you living. Just check the condition in the description, does it have fungus, scratches etc. Some sellers are not focused on selling photo related things, so I do not expect them to now how to check the condition of a lens. I prefer these guys as sellers, because they don't try to fuck you rating their stuff as "MINT", "65% of original appearance" or something like that.