How to buy used military equipment and military surplus

What equipment does the Army use?
Army Fact Files: http://www.army.mil/factfiles/
Brigade Combat Team Modernization: http://www.bctmod.army.mil
PEO Soldier: https://peosoldier.army.mil
Acquisition, Logistics and Technology:
https://www.alt.army.mil/portal/page/portal/oasaalt/documents/ASC_1009_AUSABook_Final_lo.pdf
Army Material Command: http://www.amc.army.mil/pa/about.asp

How can I purchase maps from the Army?
Contact the National Geospatial-Intelligence Agency at https://www1.nga.mil/
Related information is available from the Army Geospatial Center online at http://www.agc.army.mil