What is the cheapest way to get to Villahermosa?

I am looking to go to Villahermosa from feb17-21, 2011. I know where i want to stay, but the airfare is so expensive. I dont want to put myself in danger, so i'm not going to bus across mexico, but, i was thinkig i could find a cheap flight or something. Does anyone have any ideas of what i could do for a low amount of money?