Question Best budget gaming UPS

That doesn't exist.

Either you buy cheap UPS (simulated sine wave) and see some big time issues with your PC OR you buy good UPS (true/pure sine wave) where UPS has enough capacity to keep your hardware running long enough (about 5 mins would do) to shut them safely down during blackout.

Also, UPS capacity (and eventually price) directly depends on which hardware you're planning to plug into it. E.g 55" TV with a PC running RTX 2080 Ti will consume more power than setup with 24" monitor and PC running GTX 1060.

If you want UPS suggestions, list your system specs + monitor make and model (or part number) + any other devices you plan to plug to UPS. Also, location (e.g USA, Europe, Australia), budget and preferred runtime of UPS.