Surgery for a torn CCL and MPL repair is around $4,000. You might find it a bit less but be sure it is a board certified surgeon doing it.
Sadly many people let torn CCLs go and this is the outcome down the road. The arthritis sets in and it is very painful.
Here is a link to an article written by the surgeon I use here in Houston:
Yorkie Haven Rescue - Cranial Cruciate Ligament Tear Info