I'd guess around 250-500gp per Iron sBOD (125K-250K for a full BOD book). The rest aren't worth anything as far as I know, so I usually just give them away or throw them away.
What I throw away:
Normal DC, Shadow, Copper, and Bronze
Normal Gold 10-15 except Plate. Normal 20 LBODs except Plate
Normal Agapite 20 except Plate.
Normal Verite singles (helms and Shields)
Exceptional 10-15 DC. All DC LBODS
Exceptional 20 Shadow, except plate. All LBODs except 20 Plate.
Exceptional Copper except plate
Exceptional Bronze except chain and plate
Exceptional Gold 10 and 20 singles
Exceptional Agapite 10 singles
Exceptional Verite 20 singles
Even with the change to runics I just don't have enough space to store all the BODs or the time to fill them, so I usually just put them all into a book and sell it on a vendor for whatever default price pops up.