You asked
Best budget lens for the canon eos 850d?
For a tight budget on the 850D, I'd start with the Canon EF-S 18-55mm f/3.5-5.6 IS STM. It covers everyday shooting, and the image stabilisation helps when the light drops, which the 850D body doesn't provide on its own.
For people and low light, the Canon EF-S 24mm f/2.8 STM is a small, cheap prime that frames like 38mm on this body. My first camera guide argues that a modest body with a good lens beats the reverse, so this is the upgrade I'd spend on first.
If you shoot landscapes or interiors, the Canon EF-S 10-18mm f/4.5-5.6 IS STM gives you a wide view, like 16-29mm on full frame.
Written by Claude from this site's pages.