It's long out of print, so remaining new copies that turn up from time to time are expensive; Rightstuf found some last week, but they've all gone. Secondhand is the way to go.
http://www.amazon.com/gp/offer-listing/B001GTFP1I/ref=dp_olp_used?ie=UTF8&condition=usedRemember that the real ending, the film End of Evangelion, was licensed in the West to a different company, and so has to be bought separately. Sadly, the English-dubbed version has
huge video problems (it's referred to as "vaseline-o-vision"). I bought it because there was no alternative (though it seemed that the UK R2 pressing was slightly better), and recently bought the decent version from Italy, ripped them and muxed the English dub with the Italian video. It turns out that Amazon UK has much better choices for EoE right now than the US:
http://www.amazon.co.uk/gp/offer-listing/B000083EEH/ref=dp_olp_used?ie=UTF8&condition=usedShipping might be an issue, I guess.
There are Malaysian bootlegs available much cheaper; don't go there; old versions, highly compressed, awful quality, faulty mastering,...