Oh, those lucky Euros and their many budget airlines! They need only run a hand under the couch, pull two coins from the dust bunnies, and the ticket is practically paid for. Yeah yeah yeah, you may have to cough up a little more to check that bag full of stuff you didn't need to pack in the first place, or endure a few hours strapped into a Denny's highchair teetering atop a stack of milk crates, but who cares? You probably spent more cash on hotdogs and Diet Coke seeing Beverly Hills Chihuahua two weeks ago. And when you came out, you were still in the same country, right? So unfair.
Aside from a few limited sales from Spirit Airlines, you'd be hard pressed to find similar deals here in the States. Or almost. We do have VivaAerobus, Mexican cousin to Ryanair, flying between Austin and their Monterrey hub, as well as nonstops to Cancun and Puerto Vallarta. Currently you'll find free seats available to all three destinations, leaving you to pick up only the taxes (around $110 or so).
VivaAerobus also offers shuttle bus service between Austin and Houston/San Antonio for $20, and a $10 shuttle bus from El Paso directly over the border to Ciudad Juarez airport, where free seats on Monterrey bound flights are available for the price of taxes (about $49).