I will say it before someone else does. "So are a few other people." That out of the way, read the rules on buying and selling.
As a registered user you can go to the exchange forum and look for a 307, but you cannot discuss costs or make offers to buy one on this Buck open forum. In most instances on less friendly forums your thread would be moved to the Exchange forum and your post here deleted by the moderator. But I tell you what, I will leave your question here and lets call it a learning experience. As stated in the rules and what I will tell you now, you can't talk about the value of or buying one from this forum. You must have a Gold membership to talk about stuff like that.
We are not suppose to say the _bay. But, that place is where you are likely to find one.
If you like Buck knives, then visit and read some of the posts. Several in the past have been about 307s. If you are interested in becoming a member of the Buck Collectors Club it offers some advantages in search info from old catalogs and having people offer up Buck knives for sale. Just Goggle up Buck Knife Collectors Club to get a look at that.
Good Luck.
300Bucks, Moderator