The link that linka posted is EMS, which is the same thing as China Post. That should give you a good idea of the price though. Shipping directly through FEDEX is likely the most expensive option.
I’ve shipped quite a few packages from China to the US and I’ve found the best option is finding a freight forwarding company. I can refer you to the one I’ve been using. To give you an idea, I paid 850 kuai for a big 10 kg box.