I just bought an old used car and I am having problems...?

If you need a new cv axle the labor guides calls for 1.3 hours on the right side and 1.2 on the left side for removal and replacement. Where ever you live will determine the shop labor rate. Depending on what axle, what kind of transmission, Abs or not will depend on price of axle. Expect about $65.00 and up unless you go to a shop expect no less than $100. You may also need to replace the axle nut and oil seal. However your description doesn’t sound like a CV. You would more than likely hear a clicking sound when turning. You can jack up the vehicle, please use jack stands and wheel chalks, inspect the boot. Keep the keys in the ignition so the steering wheel doesn't lock, turn the steering wheel and wheel to get more boot exposure and look for cracks. If the boots cracked or torn you will need a new axle. If there is no tears grab the shaft and shake it back and forth if you have movement or hear or feel a knuckle like popping you will need a new one. Next problem, there is no coolant in your A/C system. It is called refrigerant(R-134) Coolant is what’s in your radiator. Used to cool your engine and heat your heating system. Your problem sounds like you may just be low on R-134. However you may also have a leak. I would advise you to find a reputable shop and get the inspection done. Some shops will apply the price of the inspections to the cost of repairs. You can get an estimate for repairs and take that to the people who sold you the car. In California the seller is only required to make the vehicle p a smog inspection unless it’s stated in a contract that there is nothing wrong with the vehicle. So you may simply ask the sellers if they might cover the repairs or pay for some of them. Good luck.