Sausage can be expensive to buy, but it's easy to make at home with a bit of effort and time. However, you may find that if you have lean sausage, it will be more difficult to break into small pieces. I usually cook it, then chop it in a food mill if i want small pieces like i use as pizza toppings.
Thaw out the ground beef or lamb, then thoroughly mix in the spices. It is best to allow this to meld at least 24 hours. Typically, i make several pounds at a time, then freeze it back up in 1/2 or 1 lb packages. Then just thaw out as much as needed.