You asked
Is the canon ef 35mm f 2 is usm worth buying used?
Yes, I think it's a good one to buy used. Cameras and lenses are built to last, and the used market is one of the best ways to get good gear for less. Buying used covers the basics.
It's a stabilised f/2 prime with autofocus, so it suits everyday shooting. It works on full frame Canon bodies like the Canon EOS 5D Mark IV and the Canon EOS 6D Mark II. On APS-C bodies such as the Canon EOS 80D, it frames like about 56mm on full frame, which is a useful portrait-leaning view.
Before you buy, test the autofocus and stabilisation if you can, and buy from a seller who offers a return option.
Written by Claude from this site's pages.