You asked
Best budget lens for the leica cl?
I can't quote prices, so I'll pick on what each lens does for a Leica CL. The CL is APS-C with no in-body stabilisation, so a fast prime keeps shutter speeds up and gives you a useful everyday field of view.
For a low-cost starting point, I'd look at the Viltrox AF 16mm f/1.8, which frames like 24mm on full frame. The Viltrox AF 20mm f/2.8 Air is small and light, and the Sigma 18-50mm f/2.8 DC DN Contemporary covers a lot of ground if you want one lens for everything.
Whichever you choose, put a good share of your budget into the lens rather than the body, and keep a spare battery in the plan, as the first camera guide explains. The full list for the CL is on the Leica CL page.
Written by Claude from this site's pages.