id say go to a hardware store, show them the bolt, and be like "i need this". thats the cheapest option, if they cant get you it, you may need to go to your shop and get one from them, but it will be about ten times as expensive
Here's my '08 Haro X6. I've rawed it and made some custom stickers, as you can see, and it looks much better than with that brown color.
I use it mostly for jumping, dirt and slopestyle/freeride-ish trails (I even got 3rd on DH nationals with it a month ago) so I've put on a shorter 190x50mm shock, to make it lower and slacker. Now I only need a smaller fork with something like 120-140mm travel to make it perfect. I really like it, now it weights in at ~15kg which is not so bad, as it's really bombproof with this setup.