Dedicated upper: BoreBuddy Economy Upper
https://borebuddy.com/product/ar22-economy-uppers/
We think that these uppers have the perfect balance of cost and features. There are cheaper uppers out there, but you'll likely still end up buying the BoreBuddy accessories to get the rifle tuned and running properly. Instead, you can get a great running upper right out of the box.
Prices range from $424 to $469 for an upper (with conversion bolt) depending on what length barrel you select.