I would suggest the eBay route which is what I just did with my devices to make room for the newest ones I am getting GN2 and a Tablet (TBD). The hard part is there are lots of them out there, but if your stuff is in good condition and you take good photo's you should be ok. Not sure how many posts you need in order to post in the marketplace but there are lots of topics you likely can impart some knowledge in and earn that spot in the marketplace.
I try to avoid the send it in and get paid when we evaluate it route. I got scammed once and never again.