It can be, but ususallyl a domsetic system holds less than a pound of gas what ever the make is. For example 134A at your proce will be in the $20.00 to $30.00 range for a full pound, dont quote me on that price, i havent contracted for about 6 years now and i havent checked on prices for a long time.
The majority of the cost will be for the technition to do the job.
DO NOT USE A CLAM SHELL FITTING AND USE AUTOMOTIVE 134A,...MAN that is sooo anoying when people do that. It jsut shows that they are just too cheep to ahve someone doit right. Have a technition braze in a fitting and weigh the charge in. The gas has to be weighed in to a critical charge,..over charging the unit is as bad as a system that is short, And running a 134A system short and letting it go into a vaccuume means a very early death for it too.
If you want more of an explanation, you can email me at:
commrefrig at hotmail dot com
I will try to answer any and all refrigeration related inquiries
Hope i have helped a bit, sometimes i tend to get "Technical" in my explanations,...sorry solong winded.
Good luck
PJ Riddick
August 2009