Started out when I was about 13 and I upgraded my 15'' Giant Boulder 500. 
 
Had this for about a year, then I built a DDG Shooter up from the frame with my xmas presents, birthday money and pocket money! 
 
That was nicked after a few months, so I bought some mega old Monty which had some crazy triple clamp style rigid forks!!! 
 
Sold it for pennies to my apprentices brother when I was about 17!