If it get thrown out will this cover the costs?
Probably not. Hopefully it will cover his short term needs, such as living-in-hiding expenses, and maybe cover the loss of income from being fired.
His legal expenses hopefully will be covered by the State of Florida, and if there is a way to set up a fund whereby he can be indigent for legal purposes, but supported by contributions (hint: put it in his father's name), I would be willing to contribute again and again.
His expenses must be very high, and I would love for him to have private security during and after his ordeal. Eventually there should be a payoff from NBC, etc. but until then he is on his own and needs our help.
He's lost from the disruption to his life, kicked out of school for safety concerns, etc. Then there is the bail, out of pocket; living "in secrecy" and any transportation associated with that, plus court and lawyer fees. Lawyer fees add up fast.
I'd guess that a quarter of a million is close to covering all that if you look just at the time from the incident to, assuming he gets immunity, to the immunity grant. He may have money left over, he may be a little short, could go either way. It doesn't cover losses going forward, and it doesn't cover the cost of mounting defamation suits.
IIRC, Mr. O’Mara is working pro bono and the lawsuits against NBC, Al Sharpton, the Black Panthers and a raft of other individuals & organizations should make Mr. Zimmerman a wealthy man. Richard Jewell X20 at least.