Congratulations on 300 found! It is a big deal to me (55 found). I thought you might want to check out this web page http://www.geomilestones.com

They sell pretty cool stickers that say "50/100/200/300/400 found" on them. I have a "50 found" sticker that I proudly wear on my Xterra! Ok, not as proudly as I would a 300 found, but I'm working on it.