You asked
Is the canon rf 200 800mm f 6 3 9 is usm worth buying used?
Yes, I'd say it's worth looking at used. My Wildlife and sport page makes the point that long lenses hold their value and change hands a lot, so the savings can be large. The Canon RF 200-800mm f/6.3-9 IS USM is stabilised and autofocusing, and it fits a wide range of RF bodies, from the Canon EOS R6 Mark II to APS-C models like the Canon EOS R7.
Since it's a zoom that gets darker as you reach out to 800mm, check that the lens works well at the focal lengths you'll use most. The buying used guide covers the general approach. If you buy a used body alongside it, budget for a new genuine battery, because old ones lose capacity.
Written by Claude from this site's pages.