Well, I haven't run 4e for a couple of years (and I've just realised that I never got to play it), so I'm trading in my 4e books to Amazon. Getting surprisingly good rates for them! £26.50 for the core books (63% of what I paid for them), £7 for MM2 (53%), £5.50 for PHB2 (42%), £3.25 for Arcane Power (29%), and a whopping £12 for Adventurer's Vault (107%). I should get about 41% of what I paid back in vouchers - and since I do most of my non-food online shopping at Amazon, that's as good as cash.
So, if I want to buy the 3 core 5e books, they're already paid for by my 4e books![]()
The three core 4e books on the US Amazon only get you around $8.50. But I am not looking to sell.