1974 - a Yashica Mat-124G. I got it brand spankin' new for $125.00 at an Ann & Hope store in Massachusetts.
I had been shooting 35mm for a while and was turned on to medium format by one of my Dad's older brothers (who also taught me color printing!). Within a few weeks, I bought both the aux telephoto and wide angle lens sets. It was one of the few cameras I wore out, though it took me a lot of years to do!