I'm thinking of buying a used 70-200 2.8 VR1 lens. I'm hoping I can get some advice on what to look for to make sure there's no problems with the lens before I buy. I can bring my camera body and play with the lens, but besides testing the autofocus and making sure it looks like the VR motor is at least humming and seems to stabilize the picture, I don't know what to test out. Can anyone tell me what to look for? Also, the price in my local market seems to range from around $1300 - $1600. What's a reasonable price to pay? For $1300 there's no accessories. At the upper end it's complete even with the box, which I'd rather have because it makes me more confident I'm not buying a stolen lens, but I don't want to pay $300 for a cloth bag and cardboard box. Thanks.