I may not have been clear on a couple of points. The Pennzoil Platinum was $11.99/qt., not the transmission fluid. And yes, they sucked it out through the dipstick.
I just looked at the O'Reilly website, and they are showing Pennzoil Platinum at $9.99/qt., so a $2 upcharge is maybe not so bad. I wouldn't pay either price for my own cars.
Also, even though it's expensive, I think that you can come by in between oil changes and they will check your fluids and whatnot, and top off at least some of them for free. So for the non-mechanically literate, it is probably a reasonable service.
Since I do most of the work on my own cars, It did feel weird to sit there while these guys did stuff.