"Freon" is a Brand name....
Please use it as such.
Refrigerant's are named by there Number and type.
x2
its R12 and R143a (only 2 that were ever approved for automobile use)
not "freon"
You must be MACS certified (which i am)to buy refrigerant in bulk (30lb tank of virgin) of both 134a and 12
for the DIY'er, 134a is available in 1lb cans but is usually never actually 1 full lb of virgin refrigerant. There is usually a die and oil added which can do more harm than good (the oil that is) too much oil in the system can cause damage as well as too little can. there for, just adding a can of generic 134a with random amounts of other s*** in it can work for a little while but do more harm in the long run as there is usually more oil in a "1lb" can of generic refrigerant that is needed for some entire systems (that are dry)
mobile A/C work is best to be done by a shop where systems can be serviced, evacuated and recharged efficiently
If you insist on servicing your own A/c, invest the money in a Gauge set to observe your high and lowside pressure and recharge with it
remember, after about 10 minutes of exposure to the atmosphere(system failure or opening of the system with out evacuation afterwards) the desicant in the reciever drier or accumulator drier will become saturated and will NEED to be replaced
do it right the first time and pay to have it done right with the proper equiptment
after you screw up your own A/C systems you can join the many others who went down the road before you and either
a: pissed and moaned at the shop you finally went to because they told you to bend over and raped you to have it fixed
or
b: removed the A/c all together