In an effort to curb a boom in wildlife trafficking, the Obama administration has announced plans to tighten up a ban on the sale of ivory.
The measure would prohibit the import, export or resale of elephant ivory, with few exceptions.
Ivory is just one example of a product that is not allowed in the marketplace due to laws protecting wildlife, historic or cultural properties. There are other bans on sales that are motivated by safety concerns, including a prohibition on the sale of recalled items of all sorts.
It's clear that the free market is not absolutely free for all.
The sale of drugs and firearms is typically regulated—and at times illegal. But there are other surprising items that may seem innocuous, yet are prohibited.
Before you look to sell items either for some extra cash or as a small business, it helps to know what the limitations are for an average citizen.
Click ahead to have a look at some objects that may once have been fine to sell, but are now forbidden.
—By Colleen Kane, Special to CNBC
Posted 21 Feb. 2014
(CLARIFICATION: The first slide of this slideshow has been modified to reflect that while some drugs and guns are illegal to sell, there certain types of guns and drugs that can be sold with restrictions.)