You asked
Best budget lens for the sony a7 iv?
For a budget pick on the a7 IV, I'd start with the Sony FE 28-60mm f/4-5.6. It's a small everyday zoom that covers most of what you'll shoot. The site doesn't list prices, so I'm going by size and the kind of lens it is, not by what it costs.
If you want something cheaper to stretch the budget, go for a prime. The Meike 35mm f/2 STM is a simple, fast-enough lens that's good for people and street work, and the Sony FE 28mm f/2 is compact and sharp enough for everyday use.
I'd still follow the advice in Your first camera: spend about as much on lenses as on the body. Browse the full list for the Sony a7 IV to compare the rest.
Written by Claude from this site's pages.