I would guess 0 is picking up less than 1% of the tab.
http://miami.cbslocal.com/2014/03/05/president-first-lady-scheduled-to-visit-coral-reef-high-school/
President & First Lady Scheduled To Visit Coral Reef High School
On Tuesday, the Chicago Sun Times reported that the Obamas are headed to Ocean Reef for a weekend of “gab and golf.” Michael Sneed’s political gossip column claimed that the family was renting “five houses on the uber-politically conservative compound.” Sneed also stated that the guests would be arriving in five helicopters. TheBlaze cannot confirm that five helicopters will be used to bring the Obamas and their guests to Ocean Reef, but a helicopter arrival is likely as Air Force One is too large for the local airport and will probably have to land at Homestead Air Force Base (about 30 miles from Key Largo).
actually I heard he was staying at the Anglers Club which is just outside of the ORC. My bet is that he probably has a list of heavy weight donors to collect from,no doubt.