Incentivized Link Building Script

I'm looking for a script that allows me to give away content in exchange for tweets and bookmarks of my blog posts. I imagine people would have to log in somehow because I would want them to receive a message after each tweet/bookmark that says something like 'Only 5 Tweets Left Before You Have Full Access to _____.' I would need to be able to customize that message as well. Upon completion of the specified amount of tweets/bookmarks, they would need to be redirected to a page of my choosing. If you can't create this, I will pay $15 if you can refer me to a pre-made script that does this already. Thanks, Adam