I was about to call shenanigans on this since like not 2 weeks ago I installed a 850 EVO for a client and paid roughly twice that for the same drive, but then I looked it up on newegg/amazon.......dang.....
I paid nearly $400 for my 500GB 840 (non-evo/pro) less than 2 years ago.
Anyways, I guess i'll add something useful: If you're on the fence about getting an SSD please jump off said fence immediately and go buy one. I've poured thousands into faster processors/graphics cards/gratuitous quantities of ram/fancy motherboards etc. nothing even begins to come close to the perceived performance boost I saw when I bought an SSD. It really is impossible to put up with HDDs once you've used a SSD for a while.
Also don't skimp and get the capacity you need the first time. I've owned a 40GB, 90GG, and now a 500GB SSD. The 40GB and 90GB ones were nice, but it was a serious pain to constantly make sure they didn't fill up. I regret not going for a larger drive in the first place, but such is life.