"Would also like to state that we are completely independent. that is, we have NO support from any companies or sponsors. We exist only by the support generated from this show. Heck pinball podcasts, pinball new organizations, etc, never mention the event. We can't even get Pinside to put us on their 'events' page. Once heard someone say, "this is the best pinball show in the world bar none, that no one has ever heard of.""
Make sure you add a Facebook even on your group and make it public. As for other advertisement: setup some cheap fliers around. All the pinball places and other related places have fliers posted for Free Play FL Pinball event every year and that show is only 35/day non-profit. If you had attendance counts or wanted to, you could try selling some vendor spots. I know some people in Toledo OH across the border that like pinball but probably never heard of the event. Check pinballmap.com and look at places that have pinball machines within an hour or so and put fliers at the biggest ones or just email them the flier graphics and they can probably just print and post for you without the need to visit.