Is $12,000 to encapsulate the crawlspace a fair price?

I've lived in my house for 4 years. I'm in Atlanta, so the AC gets used pretty much from April to October. My AC is new, just installed in November, and my furnace was installed 3 years ago. During my bi-annual service check today, the tech said my AC is sweating and recommended either a dehumidifier or crawlspace encapsulation. My crawlspace is currently a disaster; the vapor barrier is messed up, and the door is messed up, which led to a lot of water getting in a few years ago. I'm looking for advice on what to look for regarding these solutions.