I don't think there is one, and if there was I doubt it would be free that stuff is complicated programming and computer stuffs xD just google it, if you can't find one then it doesn't exist.
I am more concerned about the reason why you want it?
What is so important about gaining that one like?
There are lots of Retweet bots but they won't help you grow :/
its not about getting the like, if my username is mentioned in a tweet, it want to respond to it with at like. it shows appreciation to the other tweeter