Today I took my car to a shop and had them do an AC-check up. They told me that the car had 1.1lbs of refridgerant in the system and that capacity was 2.2lbs. Therefore they would have to evacuate the system and recharge it. They quoted me 69.90 for the service and then about 70 or 80 more for the refrigerant (and oil) at 35.00/lb. I obviously said no to this and was hoping you guys could help me do this on my own. The car is a 94 E320 and should take r134a refrig.

Can I DIY this one (for under $150) and what do I need? (refidgerant, etc.)