iPods and Fake GPS Receivers (?) in New York

Here's a photo that I took in New York a couple of months ago that features an apostrophe catastrophe and unnecessary quotation marks:


But the place looks a little shady, so maybe the quotation marks are necessary after all.

Also, since iPods and all the other items listed on this sign are plural, shouldn't GPS be plural to match? What is the plural of GPS anyway? GPSes looks a little awkward, and I definitely don't want to write GPS's. It seems that the only way around this is to write "GPS receivers," but that's pretty clunky.