I will warn you, Deer tripe stinks even more than cow tripe, and god help you if your dog pukes it back up.
Also farts. For DAYS. Eye watering, room clearing farts.
And then you'll get dogs like Enzo who want to roll in it instead of eating it. THREE baths before I could stand to smell her, and she wasn't allowed in the bedroom for a week.
But yeah, I get a lot of free stuff from my processor, but I also hunt, and so a lot of stuff comes from my own deer. Other stuff is stuff that would otherwise get thrown away, so I get it for free. If you don't hunt, and aren't providing income to the processor in that way, or haven't made friends with them, you might prepare to pay a small fee for it (if I want antlers, and I haven't gotten an antlered buck, I have to pay for them, IF they have any spares that the people who got them don't want, which is fairly rare)