Same-Sex Marriage -- Now That It's Legal ... Gay Groom Guru Is Making BANK

The Supreme Court's historic ruling on same-sex marriage means one thing -- gay wedding planners can finally cash in, and one of 'em has hauled in more than a quarter mil just today.

Robert E. Blackmon picked the perfect time to release his 2nd edition of “The Gay Groom’s Guide." It came out last month, and within a couple of hours of SCOTUS' announcement ... sales shot up by 500% … according to Blackmon's rep.

With more than 12,000 copies sold online just today, Blackmon's raked in -- cha-ching, cha-ching -- about $327,500 in revenue!!

Fun tips include how to break up family fights, selecting music for gay and straight guests (say yes to "YMCA"), and an engagement ring tip that, sorry ... totally disses Liberace.