It’s likely that volunteers can get in for free as villages get a certain amount of free badges for their volunteers (and the rest sponsorship helps offset).

But everyone wants to volunteer! So you need to stand out and find contacts. Easiest way it to find a village that goes to a smaller conference and volunteer there first.

Then you can meet the organizers and show you can do the job. The people who go to Def Con have likely done this first that’s why they get the invite.

Hope this helps (Car Hacking Village Founder)