I can order 8 recycling batteries for $2.99 and have them shipped to my house. That is a loss of $4. They are looking at an increase of $7 at least. BTW when I ship a small box 2 pound of cookies to my son from his mom it cost me around $10.
Sure, certain things will no longer be feasible. My doubt was that these less-than-the-cost-of-shipping items were the bulk of the current direct-from-China Ebay orders, and even if they were, I was doubting that there was not a market for slightly more expensive items.
For the US cost, a "Priority Mail Small Flat Rate Box" is $7.20 between any two US addresses, and a "Priority Mail Flat Rate Envelope" is $6.70. If you don't use one of these, the postage will likely will be slightly more.