Used Lenses - How much to pay??

The only used camera stuff I'd buy used are manual lenses and camera support. Otherwise I want the warranty. Especially AFS and VR lenses, AFD is less scary to me I guess. I've never bought a used lens, and probably won't ever, just save up for an additional two months.

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d800e, 16-35vr, 24 pce, 28g, 50/1.4d, 85/1.4g, zeiss 21
gitzo 5531s, RRS bh55,
sb910, 3 sb900s, 3 sb800s, 6 vintage vivitar 285hv, 3 PW flexttl, PW minittl, PW AC3
nikon j1, 18.5/1.8
sony RX100
"always just one light modifier away from greatness"