I was trying to talk a CSR into some money off last night (got no where) when she suggested I just sell my old phone (OG Droid) back to Verizon. I told her it was pointless, since I'm guessed it was worth around $20. Back and forth, she insisted on checking it in the system, I let her, and it's worth $16.
So there you go, if you want a discount, the old brick isn't worth completely nothing . . .
However, for mine, it's going to be retired, the battery drained and hid away in some drawer to look at another day. I don't think I can get rid of it since it was such a ground breaking and supremely awesome device for so long.