The only thing that's free about D/S is the equivalent to the pose room in Poser.  Everything else you have to buy.  Including magnets (DFormers in D/S) and a plugin to load morph targets.  Dynamic clothing is coming however...you get the viewer for free with ver2.0.  If you want to do any tweaking, you will have to spend $50 for a plugin and more if you want to create dynamic clothing.  If you add up the price of the plugins for the features that come standard w/Poser It's more than I paid for my P6 upgrade.  

One thing to keep in mind: DAZ has an out clause in their tellware.  D/S will only be free so long as content sales pay for it.