Should I offer a free trial or charge a small amount upfront?

Votel recommends charging something upfront, even a small amount. People who pay, even $1, take it seriously, while a no-credit-card free trial attracts people who say they will try it next week.

We apply this to the 5 Day Challenge itself, which charges a small entry fee on purpose. A free challenge would probably get two or three times as many sign-ups, but about half as many people would show up.