Bait-and Switch is their standard operating practice.
Take a cab, walk, hitch-hike, whatever -- but DO NOT under any circumstances use these liars and thieves. They advertise having a counter and cars in the airport terminal at SAT. This is a blatant lie. You'll have to take a shuttle to an off-site location, just like with every other rental agency. The primary difference is that the other rental agencies actually have shuttles that run regular routes, so their customers have to wait at the curb no more than 10-15 minutes. Advantage, on the other hand operates on the 'whenever we get there, we get there' plan. Waited outside the airport for 45 minutes in the rain in the middle of the night, and got a shuttle ONLY because I called the off-site office to ask why we weren't being picked up. Response: "Oh, he's on the way right now!". Got to the counter -- again, off-site -- cold and wet, and had the pleasure of waiting in line for another 45 minutes while their single staff person joked and laughed his way through 5 other people in line ahead of me.
I used Advantage for ONE REASON ONLY -- because they advertise that they have a counter and vehicles at the airport. They do not. This is a simple bait-and-switch technique, that will be reported to the Federal Trade Commission and the San Antonio BBB.