I doubt it would drop in price much. I only recently sold my note 3 to buy a note 4 and honestly I was quite surprised at just how well the Note 3 had retained its value. I bought a used note 3 in December 2013 for £350 and the last time I owned one (I changed phones a few times last year but ended up back with a Note) I sold it for £260. 15 months in tech terms is light years so I think the Note series are holding their value really well in general, especially now the 'phablet' is accepted among the mass public a bit more thanks to the iphone 6+