Please use our links: LEGO.com • Amazon
Brickset.com is a participant in the Amazon Services LLC Associates Program, the Amazon.com.ca, Inc. Associates Program and the Amazon EU Associates Programme, which are affiliate advertising programs designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.
As an Amazon Associate we earn from qualifying purchases.
But here is my two cents....
Check out bricklink.com and ebay, that will give you and estimate:
Check out the link, under the tab 'ebay' and you will see that there is a set (Lego 10210 Imperial Flagship new & factory sealed) on offer to be auctioned, no one has placed a bid, and the starting bid is €399,--
Check out other auctions too on Ebay. An extra note! Asking prices on ebay can be very deceptive.
Since you state that your friend build hers, and is missing a piece, it is going to be worth less. Does she still have the box? No! And the instructions? Yes! Has it been played with, has it only been build once, and only put on display? Has it been kept out of direct sunlight, to prevent or minimize decolourization, while on display. Buyers sometimes also state if this was the case, that it was only kept in a pet and smoke free house. So the bricks can be expected to be untainted: by nicotine and tar; hairs; cat-pee and what not. Al these factors may determine how much or little it is 'second hand' / 'used' still worth. When it is in a condition 'as good as new' you will be able to ask and get more for it, then when the bricks are chipped, faded prints, have tooth marks, and other signs or wear and tear, or are covered in dust or just dirty.
I don't know if I am too optimistic, but if your friends ship is in good condition, she may very well get what she paid for it when she bought it new, maybe even more, or maybe a little less considering one minifig piece is missing, and there is no box.
I hope for you other bricksetters will comment too.
Good luck with the sale, and happy brick-times with your future Simpsons Lego purchase.
Getting that for £2/£3 will more than pay for itself as others have said.
I have really fallen out with online auction places as there are too many people trying to rip buyers and sellers off, at least on brickset I feel like we have a good honest community and if there is a problem it can always be sorted. My friend bought the set cheaply and is happy to let it go cheaply too.