I use Teens by Mail from <a href="http://cgi.gammae.com/go.cgi?21651+gammacash" target="_blank">GammaCash</a>. It's 45 cents per confirmed email. Works well for me - many sign-ups and high % of confirmation. This is a reliable email program that's been around for a rather long time.
[This message has been edited by Lord Assmore (edited 09-18-2001).]