I totally agree with whats been said in this thread, when we dropped trials a while back our overall signups fell by about 20% but those that joined stayed on average 50% longer so the overall effect was more money for everyone!

And I also think you are undercharging, try bumping your prices up and don't get too discouraged if you see a drop in sales, after all if you move to $24.95 you will need less than 1/2 the number of signups to be just as successful.

cheers,
Luke