Rehab! Although neither torn cartilage nor a torn ACL will typically heal, some patients may have satisfactory outcomes with nonsurgical treatment. Middle-aged to older individuals and those that usually do not participate in activities that require sprinting and/or cutting may successfully use rehabilitation/pt to overcome these injuries. A brace can add stability to the knee. Pt will be worth the cost.
Get it fixed. Borrow the money your knee will suck without repair i unrepaired it will interfere with activities of daily living shop around find cheapest option with paymemt plan sell the car.Leaving it unrepairef is a bad choice you will regret. How did you pay for the mri?
Therapy vs surgery. Combination of meniscal tear & a acl tear usually requires surgery. If you opt for non-operative treatment, you should have an mr of the knee to confirm there isn't a clinically significant meniscal tear. If no meniscal tear demanding surgery, you may be a candidate for non-operative treatment. If, with physical therapy & bracing & activity modification, you have instability, you need surgery.
GET SURGERY. Negotiate a deal most surgeons will do it can you do lawns? Paint? Barter for something. Without surgery you will become cripple in that leg. Find surgeon who owns his onw surgery center he will deal a hospital will not but ask anyway. Have a continuous block for faster and cheaper recovery.