Compressor. I have a air condition unit that blows out cold air for a little while and then the

Question

I have a air condition unit that blows out cold air for a little while and then the air in neither cold nor hot. I had someone come and check it out and they said the compressor was bad. Is that really the problem or could it be something else? The model I have is Intertherm T3RC-042K. I just don't want to have to spend that much money on fixing the compressor and that is not the problem. If it is the problem, is it something that can be done yourself or does a professional need to do it?