On the danger list, according to Greengart: Kyocera and Sanyo, which haven't garnered much carrier support in the U.S. "Their phones fall into the 'free' and 'not free' category, and their 'not free' products aren't that competitive, " says Greengart.

FORBES: Magazine Article

And even though a large majority of games are free apps, the category is one that generates a lot of interest in a device and system from both the users and developers.

FORBES: Mobile Games On Android Haven't Caught On Yet

Some things really are too good to be true, and unfortunately, sites that offer free shipping can sometimes fall into that category.

FORBES: 7 Tips For Avoiding Shipping Costs When Shopping Online

Roku customers can download the Amazon Cloud Player channel from the Featured or Music category in the Roku Channel Store, for free.

ENGADGET: Amazon Cloud Player arrives for Roku boxes, Samsung Smart TVs

However, there's no doubt that selling apps is top of mind now for Google -- it's no coincidence that in each category, the Market defaults to showing paid apps on the first tab and free ones the second.

ENGADGET: Android Market web store hands-on Hands-on

He said the decision to swap out some previously commission-free ETFs in favor of others was made because the company wanted to offer iShares' "core" category of funds, which includes U.S. and international stocks.

WSJ: Fidelity's ETF Fee Spurs a Backlash

Laurence Toney was running Ebay's collectibles category in 2005 and tried to push through a plan to let fans of collectibles display their stuff free of charge on Ebay and then chat and post comments.

FORBES: Too Smart for its Own Good