First off.......No he's not to old to start. I started when one of my Boxers was 4 1/2, I had to feed raw due to her allergies. She took about a month to detox from all the poop in her system, it was intense! Her breath stunk, her stools, her body, she was oily, her hair was dry and brittle, her eyes weeped and she shed like a demon. After that month, almost to the day she was absolutely gorgeous. She barely shed, no smell and her stools were small, dark and had little odor. That was back in '96. All my dogs since have eaten raw, half or all. It's not cheap on the front end, we go through about 2 1/2 lbs of meat a day, the pug eats straight raw and the pit and cat eat half and half. We feed primarily beef since the pug is allergic to everything but beef, some fish and venison. The key is not to make it too complicated, after 8 years I don't really follow any strict rules except sanitation. I feed liver, heart, muscle meat(lean), veggie mix, raw bones, some dairy, eggs.......pretty much whatever catches my fancy. I have yet to find anything they won't eat, except rutabega. NONE of the dogs like it. The savings is in the long run, the medical is almost nill. I had paid my vets mortgage and financed his vacations for years prior to feeding raw. He thought I didn't like him anymore I saw him so rarely after. My pit has been in 3 times in her 7 1/2 yrs for injuries. My pug has seen him 4 times in 5 years. The dogs are disgustingly healthy and with the bones I don't even have to have dentals done on them. The last dental I had to pay for was for a rescue that had rotting teeth when I got him. It takes a little time for them to develop the enzymes to digest raw, about a week. Yogurt goes a long way to helping with that.
As to monthly cost? That depends entirely on how you decide to go. I buy from the grocery store, lower grade cuts, flat iron steaks, chuck, nothing ground. I pay anywhere from 1.10 to 2.00 a pound. We go through about 16 pounds a week and we get about $20 in veggies and it lasts about 2 weeks. Hope this helps.