David Bowie "Ziggy Stardust" -- a cutout LP in the bargain bin at the mall for $3.10, circa 1985.
First cassette was The Police "Zenyatta Mondata" a couple years before.
First ever, ever record purchased was the 7" single of "She Blinded Me With Science" by Thomas Dolby -- I was very disappointed that the mix was differrent than the radio hit version (though now I'd probably prefer the "funkified single mix" better . . . )