Can you sell an item that did not sell on Ebay elsewhere?

Here is the deal, I listed a bunch of Nerf blasters on ebay. Some did not sell. My gf said there is a rule on ebay that you are not allowed to sell the item outside of ebay for a set period of time without risking ebay canceling your account. What is the deal here? I have searched for a few hours on the ebay website for the info on this and found nothing.