This Mashable article argues that SMS (text message) marketing "still makes sense" for small businesses. Huh? Since when was there ever a question about whether it makes sense?
Not only is text message marketing relatively cheap, you can reach highly targeted prospects everywhere. Millions of people all over the world have the ability to receive text messages, including probably every camp family you know.
Marketing to people on their cell phones works -- in fact my wife just received a coupon for Toys R Us on her cell phone, then went right in to redeem it -- and if I were you I'd definitely look into this strategy.