Anyone know if the lockout is affecting preseason ticket sales?

British family planning a big holiday in the US this year and wanting to go to an NFL preseason match at Reliant Park in Houston on 15th August (Houston Texans vs NY Jets). Going for the experience and the atmosphere as my teenage sons love American football (who doesn?). Anyone know if the lockout and the economy will mean that I can get tickets when I am there or will it be sold out? Are preseason games usually sold out well in advance? Dont want to buy the tickets now and find out I could have got much cheaper ones in Houston! Any advice much appreciated.