title: What are the options to implement a Groupon like system?
body: <p>I like to build a system that will allow users to "commit buy" a deal, but will only be charged after a minimum # of committers are reached. The time span in which the "deal" will continue can be either weekly or monthly.  </p>
  
  <p>I like to stay away from building one from the ground up as much as possible.</p>
  
  <p>I know there's another thread on StackOverflow that asked paypal, amazon, or google checkout API to serve this purpose, but this seems too much like a hack?</p>
  
  <p>I did some reading on using a gateway like Authorize.net to process credit card information and they can store the user information and has a service like pay-as-you-go. Would using their API be a better choice? Can their pay-as-you-go method provide the system that I'm looking for?</p>