OnePlus still sells the vanilla version of its 2021 flagship smartphone, the 9, for US$729 on its official United States website. However, Best Buy offers the same device (unlocked) for as little as $549.99 - so long as it is activated via the chain's website or physical stores on the same day on which it is ordered. Alternatively, it can be had for different discounted prices without this caveat.
https://www.notebookcheck.net/Get-the-OnePlus-9-for-just-US-550-for-a-probably-limited-time.549300.0.html