Amazon seller: Potensic
Price: $110 with coupon
This vacuum was $80 with a promo code just the other day, but that has expired. Even so, you can still get it for $100 with the coupon that has appeared on the product page.
This is about as basic as robo-vacs get, but it's also one of the lowest prices I've ever seen. The 22T isn't laser-guided, so it'll just bounce around your floors until it needs to return to its charger (which it'll do automatically). If you want to keep it out of certain rooms, you'll need to put down a strip of magnetic tape, which is included with the vacuum. You can't even control it by app; it relies on a handheld remote.
But if you just have, say, an apartment or small home to clean, this sucker will do the job without complaint. And that's the goal, right?