Was you robbed you paid 80 a lb for freon in your home AC unit?

That's actually lower than most markups. I'm guessing you have R410a refrigerant, rather than R22 - you'd almost certainly pay more for R22.

You can look online and see the cylinders cost considerably less per pound, but you need to be EPA certified to buy them. With that price you pay per pound, you pay for the technician's technical knowledge and experience, and also liability, as well as your refrigerant. Compared to what I've been seeing HVAC techs charge for refrigerant, you actually seem to have gotten a pretty good deal.