My AC hasn't worked in 6 months, shop said I need a new compressor, but randomly when I cranked my truck today its blowing ice cold! Lol I don't wanna kill my truck!

 

Maybe a weak clutch. And sometimes it works sometime not. When its not blowing cold see if the compressor clutch is NOT engaged. Sometimes when that happens you can tap the clutch and it will come on. That can give you piece of mind the compressor is bad. Maybe get 2nd opinion too.