I'm planning a trip to visit family in Austin in June. I've been a couple of times before and usually get a Continental flight from Houston (IAH where I land from London) to Austin but this time the dates I need are coming up pretty expensive (around $200 each way, previously I've paid half that for the return trip!).

I need to do this vacation as cheaply as possible so am looking for a more affordable way to make the trip. Any suggestions? I gather there is a Greyhound that only costs around $35 but I can't seem to find details of where in Houston it leaves from.