The first record I ever bought with my own cold hard cash was Black Sabbath's We Sold Our Soul for Rock 'n' Roll.
I remember I heard some dude in my neighborhood talking about a mysterious singer called "Ozzy." I was completely enthralled, so I formulated a plan.
To obtain the cash to buy the record, at 13-years-old and no job, I had to resort to drastic measures: selling some comic books! After getting hosed on a bad deal at my local comic shop, I got on the bus to Sam Goody in Queens Center mall and bought that album on cassette. After hearing the whole Sabbath experience, I was completely blown away. I actually sold my whole comic collection and bought all the Sabbath records as well as Van Halen and Iron Maiden.
Moral of the story: Sabbath is a gateway drug. Also, I still own that tape. It is virtually indestructible, it has survived multiple band tours, several moves and a car fire. Satan laughing spreads his wings...