They are worth every penny for my dog! Her #1 toy choice is stuffed ducks (she guts them, ignores the stuffing, and plays with the carcasses), but she refuses to play with anything more durable- no Kongs, no ropes, no balls, nothing. We’ve given her cow bones from the butcher in the past, but she destroys them in less than 10 minutes, not a drop left.
Luckily on a visit to her cousin’s house, our dog decided she really liked the elk antler they had, and she barely put a dent in it despite chewing for a good hour.
So we bought her one and it took her a month of casual use to remove the marrow part, and she is still barely making a dent in the bone part (and she still chews it!). Well worth the money.
We get ours at Country Max, but we’ve also found them at little “mom and pop” type feed stores in our travels.