According to the story, the money was from donations to his PayPal account. I certainly hope the Martin attorney hopes to get paid, and expects that Zimmerman’s attorney wishes to get paid as well.
There's no question in my mind that the Martin "Attorney" is just an ambulance-chaser, and has a large contingency-based fee in mind, when the Martin's sell the movie rights, book rights, talk-show appearance money, and a GIANT civil suit against the Taxpayers (City of Sanford, etc.), as all these "Cause-based" meritless extortion schemes play out.
Zimmerman's defense attorney would be on a standard-rate deal for him, and he needs cash to pay.