In the United States, at least: There are retail stores - brick and mortar, I know! - where various “beauty supplies” are sold. Find one where they sell hair bleach etc. They will also sell hair shears.

I got the second-cheapest set they sold, for around $25. For our amateur purposes, these student-hairdresser-grade shears are more than adequate.

I cut my own hair probably 6-9 times a year, and those shears are still the sharpest things I own, fifteen years later.

(Shears are actually really specific cutting tools. Mine have only ever cut hair, which I credit for their long life)

You're probably going to find that hair-specific scissors are going to work fine on beard hairs too, but they'll be comparatively long and ungainly for around your face.

Any brand-name ones are going to be good if you're not planning to be a pro. I do my family hair, but that's with a trimmer!

Apparently it's hard to find stuff. I'm also left handed but it was difficult to find affordable lefty barber shears.

I thought about just getting a righty but the decent looking sub~$30 ones that people were recommending online all had the offset handles which would be extra uncomfortable.

Anyway. I ended up ordering this so I'll let you all know how it turns out: 5.5" Left Handed Professional Barber Scissors Solingen Hair Cutting Sharp Shears https://www.ebay.com/itm/254784385585?