>>Market rate from Shenzhen to Long Beach to ship a >>container is about $1200 right now

Just so there's context, the actual cost is much, much higher than $1200. That's just the payment for the ocean journey. The other costs are factory to port (varies), insurance+docs (few hundred), destination port charges ($1k or so), customs bond, and then the actual duty for the imported items. Lastly, of course, getting the container from the dock to where you are to unload it.