2003 Ford Taurus 03 A/C went out again

Air Conditioning problem
2003 Ford Taurus 6 cyl Front Wheel Drive Automatic 57.500 miles

Hi guys, I'm back I originally asked for help back at the end of last yr about my a/c blowing warm air on my 03 taurus. I told you I went to Pepboys and they wanted to charge me 1200 for a new compressor and they ended up charging the a/c for 116 instead, well that fix worked for a couple of months and now my a/c is blowing warm again. A friend of mine put in 3 cans of freon and it worked that day perfectly but then we got a cold front and lately I havent' needed to use the a/c now the weather keeps changing and its alittle warm and when I tried to turn on the a/c again no cold air. Do I need to have them test with dye to see if there is a leak and is that expensive to fix? I still can't afford to replace the compressor with a new one. Could it be a seal broken somewhere on the compressor or am I stuck and won't have an a/c at all. Any help again would be greatly appreciated.

Deb