For those of you who run bootcamp style training, do you use promotional materials like t-shirts, water bottles, baseball caps?

I’m going to be starting a bootcamp at the start of the New Year and am considering taking Todd Durkin’s advice (based on a great session I took of his at the IDEA World Conference this summer). He’s recommended purchasing t-shirts and the like. Do any of you do that?
Also, do any of you use an auto-pay billing system? If so, how does this work for you? If not, why?