I’m afraid your budget is at the low end of anything half decent.
For that price i would look for a 2nd hand option on a better spec machine. Luckily treadmill pierces 2nd are very low so you’ll get something in budget.
You’ll also have to consider additional costs such as a device to send speed/cadence to Zwift as again at that price point you’ll not get a smart treadmill.
Or you could consider an interest free option on a new one if you don’t have sufficient funds up front.
I’m an ambassador for NoblePro so can steer you in the right direction.
If you’re in East Yorkshire you’re probably just across the Humber from me if you wanted to see my treadmill in action to see how good the NoblePro is.