Air Conditioning - Everthing seems to be working.. But Air is not cold

Outside fan and inside fan running. All fuses good, and most importantly the compressor kicks on and is also running. But line from compressor is not getting cold, just a lttle cool. What else can I check. Its been about 3 years since the last time it was charged. But I was told that should be sufficant...Unit is about 8 years old....Anything else I can do??? And if I need a AC Charge or leak check does anyone know how much it would cost or at least a fair amount it should cost? Thanks !!!:(

The system should never need to be recharged so it sound like your have a leak. Freon should cost about 30-40 dollars a pound. Your probly about 3 pounds low depending on size of unit. But you probly want a leak search done so your not doing this again in two years.