Now, I was wondering about this piece. I have seen sistermates sell for maybe $2,500 - 3,000 in previous auctions without the background. But, this is so far going for $13,000-ish. However, there is no mention of there being an actual background in the description, and yet one is being shown.
There are also 50 Limited edition re-prints of this image and background that Gainax produced & released back in 2000/2001 for comiket (I think it was). Each 'cel' (complete with sequence number) was a reproduction & came within a specially designed frame with numbered plaque, copy of the genga & authenticity certificate. These of course sold-out within the first 10minutes. On the few instances one has made it to the Open Market, the last price attained was in the 1,000,000yen mark.
I would be asking the question, is this the original 'master' or one of those limited re-productions?