Your best free option is to use an online conversion service. With these services, you upload your PDF file, then download the converted file.
I tried a number of these services, including one offered by Adobe, but in the end I could only recommend this one.
ZamZar. is an excellent general file conversion site, and PDF to DOC is one of the many conversion options available.
Usage couldn't be simpler: just surf to the site, select your conversion output type, point to the file you want uploaded for conversion and type in your email address. Some time later you will get an email with a download link for the converted file.
For my 107KB test PDF file, the download email link came back to me within one minute, which was pretty impressive, though I have heard that sometimes you may have to wait for quite a while.
My test file is in multi-column format with breakout boxes in various font styles and has embedded images. Converting this is quite a challenge.
ZamZar did well, though. The two column layout was preserved, the images were reproduced in their correct locations and the varying fonts rendered well, given that Word had no exact matching fonts. Importantly, all the text could be edited from within Word
On the downside the image quality was reduced and the article's large opening drop capital was displaced. Not bad though.