I recently attended Drupalcon London. This was my third Drupalcon and as usual it went by in a flash. At the moment I'm working on contract in London with some other drupal developers who didn't attend so I wanted to point out why I think attending the conference is more than worth the minimal cost.
For me the biggest part of Druaplcon is meeting old and new friends, putting a face to that irc nick and having a chance to speak to other people in and outside the community... and beer. I always come away from the conference with a real vigour and energy to learn more and contribute more so for anyone who is thinking about dabbling in the community going to a con really kickstarts the process. The sessions are a bonus too and there were some great ones this year.
Jeff Noyes did a great presentation on design and the user experience - http://blip.tv/drupalcon/creating-and-measuring-the-user-experience-5493654
Larry Garfield's presentation on "code smells", was really well put together and informative - http://blip.tv/drupalcon/this-code-stinks-5491210
Kristof De Jaeger and Jan-yves Vanhaverbeke's presentation on Display Suite made me wonder why I had not used it before - http://blip.tv/drupalcon/take-full-control-of-your-site-layout-with-disp...
Thanks to @NikLP, for pointing out the feed to the video's at http://blip.tv/drupalcon/rss
Back to the subject of getting your moneys worth - whilst at the conference I managed to speak to several people whom I can envisage working with in the future and the week after I was asked to do some work for someone as a direct result of speaking to them at Drupalcon.
All in all as tech conferences go I think Drupalcon represents great value for money and an enjoyable experience.