For a second-hand DS box set, prices start at 500€, but it all depends on the condition (wears and tears, scratches on CD...). I guess a sealed box (i.e 'out of the factory') is worth 850+ nowadays ; in any case you should precise the number of the box (out of 3,500), the lower the better. Good luck!
As for the DVD Little America, there is a demand too (for ex. see here
https://www.alphaville.org/showthread.php?t=3736)
No idea of the reselling price, I only know I got mine for 45ish € when it was released. The good thing about it is that it's a zone 0 disc playable worldwide.