Free commercial real estate marketing sites for leasing

[Aubrey P.]

Can anyone recommend some good, free alternatives to paid sites like Loopnet, Costar, Cityfeet for marketing office spaces for lease? I have several buildings and units and they're currently listed on craigslist and commercialsearch. I would appreciate learning of other good resources (free sites, listservs, etc.). All properties are situated around Capitol Hill in Washington, DC. and I am not a realtor, so I don't have access to the MLS. Thank you.