I would never opt for conservative treatment for a torn CCL. That is condemning a pup to lifelong severe arthritis. It also leaves the knee very unstable and the other knee will more than likely tear. They are at risk of that happening anyway even IF you repair the first, but it is at least less of a chance. Without a repair, they will start using that leg again, but at a high cost...arthritis and pain! Some people get fooled into thinking the pup is just fine because he or she is walking on it......the problem is the pups often will not show pain and that does NOT mean they are not in pain!!
As to the cost....in this area it is $4,500 for TPLO repairs. But, in my experience the pups recover very well. I have had quite a few of them done over the years on my own and my foster pups.
Here is a link to something the surgeon I use wrote about torn CCLs....
Yorkie Haven Rescue - Cranial Cruciate Ligament Tear Info