Planes that cost in the billions? Equipment for the government is never cheap, mostly because they can't get economies of scale pricing. And not to mention that year-to-year changes can give you excellent information too. For example: say last year they spent $10b, and this year they spent $20b -- holy crap they clearly expanded something or bought some crazy expensive gear.
It's an intelligence agency. Most of what they do should be classified.
Here's a thought. We don't need them and they do much more harm than good. They didn't protect us against 9/11, mislead us into Iraq, took 10 years to capture Osama Bin Laden, didn't foresee the collapse of the Soviet Union, and now are mucking about with Syrian "rebels" (and indirectly supporting Al-Qaeda) fomenting the start of WWIII.
If they just didn't exist we would all be safer and we'd get to keep more money. By falsely leading us into war in Iraq for absolutely nothing, they effectively cost the US over $10^12. The cost of the CIA and other agencies is much higher than their yearly cost. They can't even manage their sys admins, why should we trusting them so much?
It's an intelligence agency. Most of what they do should be classified.