Wow, I paid a guy that did mobile car washes about 4 times that to come do my car inside and out. He did a better job than I could ever do. No way in hell I'd let someone touch my car for $16, you get what you pay for lol.
I feel bad for the people that wash their cars after me when I take my truck through the drive thru and that's why I won't put my mustang or any car I drive with decent paint through one. Wash it at home or if you use a do it yourself bay make sure you take your own mitt or towels instead of using their brush, most people have no clue how much dirt and crud gets left behind in those brushes and drive thru car wash scrubbers.