I am thinking of buying a "used" Canon EF 70-300 f/4-5.6 IS USM lens. The guy selling it says it was the kit lens included when he bought a new camera, however he doesn't need this lens, and has never used it. Canon msrp is $649, Adorama, and Amazon are selling it for $435. The guy wants $380, but for $70 more I can buy brand new w/warranty from reputable dealers. I don't want to be a lowballer but for the previous reasons I thought I'd offer him $300.
What do you think about this lens?
I have never bought used camera gear before so I am a little hesitant. What are things should I look out for besides the obvious things like cracks, dust, dings and excessive wear marks? Where is the build date code? How do you read the build code?
I will be using this lens for shooting my grankids soccer and baseball games and outdoor motocross races.
Any advice you care to offer will be kindly appreciated.