Most establishments that still service R-12 are charging about 60 bucks a pound, and you have to add something for labor.

There is an A/C label on the radiator support that lists the capacity of the system. For my '88 190E 2.6 it is 1.0 kilograms, which is 2.2 pounds, or about 35.2 ounces. The vapor pressure of R-12 at room temperature is about 70 psi, so if the initial system pressure check shows less than about 70 psi, there is no liquid freon left in the system.

I believe EPA requirments require the licensed R-12 tech and establishment to check for leaks and not let the car leave with a R-12 charge if any leaks are found. They have to either repair the leak or evacuate the R-12 if the customer chooses not to have the leak repaired.

Whoever does the work, make it clear that you want recorded the initial system pressure and how much, if any, freon they recover from the system when it's evacuated.

Duke