FWIW, when I was a student at Fredonia State college in NY, I made an effort to attend any free or low cost music event (which included at least one opera, if not more). While all were sparsely attended, they were always attended, and not necessarily by just the same few folks. That was kewl because Fredonia is a very small town and all the nearby towns are also pretty small. I really can't do any of that, now: I live too far away from anyplace to go unless it's a weekend. In other words, attendance might also be a little dependent on
where you're playing.
Another thing is that if I know that a group that's even partially interesting to me happens to be playing even somewhat nearby in the near future, I can make plans. For me, it's helpful to see something like, "Playing at The Old Oak Theater, near the
US 60 and the Loop 101." That little location detail tells me that it's 15 miles away, rather than 80.
Also, again speaking as just a person from the general public, if your
promotional material looks terrible, I'm going to skip it.
I also heartily recommend that there's some way to get your audience on an e-mail list AT the concert. Get people to write down e-mails and put 'em in a bag or something; don't rely on a line of text in your set list. While I'd make the effort to get on your mailing list if you're good, a lot of us are lazy. Hey, I can't go to your concert if I don't know that you're playing.
On a different subject, a lot of churches have
really good acoustics and sound gear and would love for you to pay them rent. I know this from ... being a pro church musician and head of a church music department. However, availability might be limited. Most of the churches I've worked at/for have the main auditorium in use on Saturday, Sunday, Wednesday, and usually Friday. But, if you want to rent the place and clean up, we'd be happy to even provide music stands. Heck, if you're really nice, we might have some tympani or something y'all can use.
However, I love youse guys, but your prices are a little high for me. My cut-off is the price of a decent CD, and
the last one I bought was about $9 (I preordered. Album review: average). I definitely like the, "Kids under 15 (whatever) are free," but I probably wouldn't take my young'n. (Oh. Churches also generally have crying rooms that have audio pumped into them. Another benefit!)