NEW YORK (CNN/Money) - Think America is a free market, where anything can be bought for a price? Actually, there are a whole bunch of products the United States government won't let you buy legally.

Back in September, CNN/Money highlighted a number of food items you just can't get here. (Click here to see that story.) Certain other goods are illegal, too.

The reasons for product prohibitions vary. In some cases the government doesn't think the product is good for you; in others, it doesn't think you're good for the product.

Under the first heading, for example, come some natural pharmaceuticals. Under the second, you'll find animal products taken from the wild.

These bans do not enjoy universal support; some are under near continuous challenge. As the conditions that contributed to the pressure to instate the bans improve or change, the clamor to revoke them strengthens. Many are products that have been utilized and enjoyed by human beings for hundreds or thousands of years.

More and more Americans have taken an ethical stand -- especially on the treatment of animals -- that has bolstered the cases for prohibitions against certain animal products. Furthermore, as the populations of some species have declined, the government has adopted bans in an attempt to preserve these animals from extinction.

Whether bans help or hurt that effort is under almost constant debate in conservation circles.