Full text articles are free and must be made available to the general public if NIH funds the work, but yes, you need paid access in order to get the pdf version. You get essentially the same information, just in a prettier format. Any serious scientist in a decent research lab has access one way or another and can load the pdfs onto a MBA.
There's a bill in the senate right now that would rescind the free access provisions. The scientific press wants us to fund the research and then have to pay to see the results.
The driving force behind this is Senator John Conyers, D-Michigan.