Lots of glaring stuff pointed out so far, but for me, the idea that you would:
1) give a price on the phone without a paid service visit
2) think that being just out of school you are qualified to quote more than a ham sandwich
3) then wondering why the guy did not call back
all adds up to you being in WAY over your head.
Get with a good Co and learn the ropes. A call for a specific repair is indeed what you identified as price shopping. Which means that all of the effort you spent during the call to waste the energy required to maintain respiration, much less calling a supply house to price the compressor was....wasted energy.
Now that you know these things, take my advice and do not delude yourself into thinking that you are ready to hang out a shingle, and get some experience in what customer vetting looks like.
And welcome to the site.