I get generic soup bones from the store (Knuckle, femurs, etc) - they come frozen and Emma loves them that way. She has the outside clean in an hour....then hides them around the house and in the couch They last a week, before they start to smell.
If you're just looking for general things for your dog to chew on, I suggest elk/deer antlers. They're kinda pricey (between $10 and $25 depending on size and where you buy them), but they last so long. Also, bully sticks/springs.