Virginia is a control state, and its retail prices are online at www.abc.virginia.gov/Pricelist/price.html while Washington DC has an ABC Control Board overseeing licensed private stores. I quote prices paid before tax.
Va's is about 4.3% while DC's is about 6%. In late 2013 WDC increased its off-premises spirits tax to 10%. Makers in DC (like Green Hat Gin)and wholesalers bringing spirits into DC pay $1.50 per gallon. See http://otr.cfo.dc.gov/node/232962 for more detailed info.
Va ABC price for a 750ml of MM is $29.99 while stores in DC offer it, before specials or discounts, at $30.99 to $32.99 depending on the neighborhood.