Depends on how extensive a conversion you want to do. If you want to a complete conversion and replace just about everything, the cost will be in the thousands. For considerably less, you can replace the refrigerant oil, replace the hose fittings, and replace the metering device. Another alternative is to switch to R414b, which is claimed to be able to replace (read: replace, not be blended with) R12 without a need for changing oil or components.
First off it contains no Freon. The refrigrant used is not Freon R12 but is R134a. Freon is extremely expensive but R134a is around $7 per 12 ounce can.
$39.95 @ Wal-Mart
None, the refrigerant is R134a not Freon which is R12.
The system will take 30 ounces of R134a freon.............
28 ounces R134a
It does not take Freon. It uses R134a refrigerant.
It depends on the year and witch type of freon you have but on a 2003 model it will take 1.6 pounds of R134a freon................
2.0 lbs R134a
1lb 3/4 of r134a
R134a OEM charge is 29oz or 0.74kg
$7.99cents
In order to remain compatible you should use the same type of freon that is in the system already. If the system has not been converted to R134a it would have R12 in it. R12 is much less used now and more expensive than R134a. You might want to consider having it converted to R134a If it has been converted to use R134a then use that freon.