No. Everything on the site is FREE.

--Forums are FREE
--Selling is free (unless you want ad enhancements)
--Product Guide is FREE
--Magazine Reviews are FREE
--Community Services are FREE
--Club Services are FREE
--RCUniversity (when it launches) will be FREE

NOBODY is required to upgrade their membership (even though there are many benefits to do so)

--You may buy and sell in the Marketplace FREE and WITHOUT placing your credit card.

--Upgrading your membership saves you money if you are active in the market. It also gives you other benefits (to find out more click the "Upgrades" button atop any page (when you are logged in).

For more info, click the "Upgrade" link in the upper right corner of any page (you must be logged in to see it).