My Bichon has a torn acl possibly. Any estimate on cost to repair?

My Bichon is 5 years old and I really want to do what I can for him. He had a test done on his knee joints last week for joint fluid...all normal and immune system (cells) normal. While he was sedated the vet checked his knee caps. Left slightly loose but right could be moved all over the place. That is why they beleive he has a ligament issue AND a torn Acl possibly. I will get prices in a few days on surgery costs. Just curious if anyone else had a knee surgery done on their dog and how much $$$$? No insurance.