Hare Today is a good source, and there are a few others that ship raw meats for dog food.

But also keep an eye on sales in your local grocery stores. I usually can buy chicken thighs for 99 cents a pound and short dated meats are often marked down. I scored yesterday afternoon right before Christmas as one store marked much of their meats down to 1/5th the price! Got some $15 steaks for $3 and chicken wing packs were $1.20 for about 2 pounds of the organic chicken.