NEW YORK (AdAge.com) -- When California opens its doors to same-sex nuptials this week, it will be a boon for its economy and savvy marketers. The wedding industry pumps billions into the coffers of retailers, hotels, florists, bands and caterers each year, with the average price of wedded bliss now tallying $28,704, according to the Wedding Report. Wedding planners hope that gay marriages in California will eventually become a profitable piece of the business.

A study conducted by the Williams Institute at the University of California, Los Angeles projects that the Golden State will see $683.6 million in direct spending over the next three years, thanks to California couples and out-of-state couples flocking there to seek same-sex marriages. During that same period, the study projects 2,178 jobs will be created in the state to service the industry.

In total, the study, authored by Brad Sears and M.V. Lee Badgett, estimates that in the next three years, California will play host to 51,319 resident couples and 67,513 out-of-state couples tying the knot.

"For over 20 years, analyses of other states' consideration of opening marriage to same-sex couples have argued that the first state or states to do so would experience a wave of increased tourism from out-of-state couples that would bring millions of additional dollars in revenue to state businesses," the report states. "In the spring of 2004, the issuance of gay-marriage licenses in Portland, Ore. and San Francisco provided support for these predictions. ... Furthermore, in anticipation of the availability of same-sex marriage in Massachusetts, cities in that state experienced a spike in hotel reservations, catering requests and other wedding-related orders."

Richard Markel, association director of the San Francisco-based Association for Wedding Professionals International, estimates that the average same-sex wedding costs about $15,000 and includes 40 guests, based on figures from 2004, when San Francisco allowed gay couples to marry.

Prenuptial concerns He said some vendors are already advertising in anticipation of a windfall, although he suspects many are taking a wait-and-see approach and will ramp up marketing in the weeks to come. Indeed, with a voter referendum on the matter slated for the November ballot, it's likely that marketers and couples alike will proceed with caution.

Wedding planners hope the events will eventually become a profitable piece of the business. Mr. Markel said 98% of the group's 790 members plan to work with same-sex couples.

"With luck, the parties will get as big, if not bigger, than heterosexual weddings, which would be great for the economy," he said. "To me, the real money will be if couples come into California. They'll bring guests, and those guests will stay at a hotel, eat and shop."

Tapping into guests' wallets is a strategy Macy's is already employing. The retailer has run full-page ads for its wedding registry in the Los Angeles Times and San Francisco Chronicle, which read in part, "First comes love. Then comes marriage. And now it's a milestone every couple in California can celebrate. Let Macy's Wedding Gift & Registry help you start your new life together."