I've got a few ranging from cheap to custom. These are (believe it or not) Victorinx Paring knife, Cold steel bird and trout, and Gene Ingram bird and trout. I personally get more use out them while wading and fishing rivers than hunting. Gene Ingram sent me the b&t with both a Kydex neck sheath and a leather sheath. Most of my "neck" knives are carried in the pack while hunting.
The top pictured Victorinox paring knives are about the best kept secret out there. I usually buy the 3.25"ers by the dozen. They come in both plain and serated edges and are cheap. I get for 3-4$ a piece usually. While I have resharpened them, you don't have to at that price, You can just toss them. The Kydex sheaths for them are harder to find. A buddy who lives in Alaska sent me the one I have. He says the knives are very common up there and they have quite a few different sheath options for them up there.
This is another Ingram necker I have. This one is a scaled down drop point. This one I do carry quite often, and I do use it as a daily carry knife as well.
bottom knife in this pic is the small Ingram from above.
Bottom line is that there are options for a guy to try a neck knife to see if he likes the concept without spending a boatload of money.