This is a classic mistake I've seen before in front of various convenience stores. It's not as common anymore because old signs are being replaced by new signs, but I caught this one at a rundown, ghetto, deli-mart in the town next to mine.
Correction: If you haven't already caught onto what is wrong with this, allow me to explain. "ATM" stands for "Automated Teller Machine." Understanding this, the sign would be read "Automated Teller Machine Machine Available." New sign creators have realized this and have dropped the second machine. Took them a while though to figure it out and they were able to get away with it, too. Apparently, what "ATM" stands for isn't common knowledge, hmmm...