You asked
Is the panasonic lumix g 8mm f 3 5 fisheye worth buying used?
I don't list used prices, so I can't tell you whether this lens is a bargain today. The general case for buying used still applies, though. Lenses and cameras last a long time, and used gear is one of the best ways to afford good kit. The buying used guide covers what to check.
The Panasonic Lumix G 8mm f/3.5 Fisheye only fits Micro Four Thirds bodies. It frames like 16mm on full frame and isn't stabilised, so it's a fun, wide lens rather than an everyday all-rounder. Two compatible bodies to consider are the OM System OM-5 and the Panasonic Lumix G100.
If you buy a used body with it, budget for a new genuine battery, since old ones lose capacity.
Written by Claude from this site's pages.