I realized this weekend that my long-ago comments on consumeables were lacking.
Kibler's Bits are a cheap, easy way to buff your ghoul as an unholy DK. Your pet gets 20 strength and 20 stamina. On most servers you can find the buzzard meat for 20-50 silver, or if you're bored you can farm them up easily in Hellfire Peninsula without competition.
On the other hand, min/maxers should know that Spiced Mammoth Treats are in fact, better. It gives your ghoul an extra 10 strength and 10 stamina. They also cost more, with mammoth meat being a northrend meat and is used in some decent raid foods, particularly by non-fishermen/cooks - and a northrend reagent (Northern Spices). It may run you any where from 1-3.5g depending on your server.
So why would you spend so much more on each and every progression pull? BECAUSE YOU'RE A RAIDER!!!
I've been using the mammoth treats for some time now.
Gold is easy to come by, so buying the meat and spices should be easy. If there isn't much meat on the auction house, just note someone who puts it up for sale a time or two and send them an in-game mail offering them a low price if they want to regularly supply you with say 3 stacks of meat a week. Have them COD it to you. I've done this on multiple servers and it works like a charm.
If you prefer to do so, however, farming the mats is very easy. Do the daily cooking quest for your spices, and then occasionally run to Dun Niffelem (far east corner of Storm Peaks, where Hodir Reputation dailies are) and kill packs of roaming mammoths for the meat. There are also many mammoth packs in Sholezar Basin and Borean Tundra, but it takes longer to get there.