I did pretty much the exact same thing as the OP - my brother and I traded in our entire Mega Drive collection to Cash Converters to raise cash for a Nintendo 64. On the plus side, we got Mario and Lylat Wars and rather than trading it in we played the shit out of it. And then Goldeneye came along...
Ever since I've tried to rebuild my Mega Drive collection, but 9 times out of 10 the console itself doesn't work!