Skip Payment Button

Can anyone tell me how I might add a "Skip Payment" button to the Payment Methods page during checkout?

My customers can access products through a subscription plan but I also want to add the option to buy. I can use the current settings for the option to buy but I need a way to let them continue with checkout without paying for individual products.

This post may be helpful.  Check out the one I left "initdotd" on 3.22.2010. http://bit.ly/9sQo3A