A/C blowing hot air

The A/C in this car has not worked since I bought the vehicle. The guy said maybe it had a leak. I took the car to Pep Boys yesterday to get a free A/C check because I don't own a gauge to get high side readings. The guy came out got me I have filled it up with Freon he verified that it had Freon and the compressor clutch engages correctly. So I was thinking it was fully functioning because visually it engages and disengages like its supposed to be. He said that the levels are about where they should be but that they are supposed to drop at a certain point and that they were not doing that. Keep in mind this is a free check and I didn't have the $61.99 for a better check. He suggested that maybe there was a block or something else wrong with the compressor and suggested doing that and replacing the dryer.I have replaced an A/C compressor before on another vehicle, but I don't know all there is to learn about A/C systems so I don't really understand what could be the problem. It blows fine and decent just hot air even when I filled it all the way up. It is like a blow dryer to the face and here in Texas summer heat it is getting a little unbearable I need to get it working ASAP and don't have much money to spend so I want to be sure of what the problem is. What else could have failed inside the compressor and what would be the cheapest way to go about getting cool air back?