It depends. At $500 a team, you'd gross $9,000 based on 18 teams in a shotgun start. That should hopefully cover all expenses of the tournament. Where the money is raised is at the awards presentation at the end. Whenever I've played in charity tournaments, there is always a pitch at the end to raise donations. Many teams arrive prepared to donate heavily.
That being said, while a golf tournament won't necessarily bring in TONS of money, this could be a workable idea. Instead of $500 per team, I'd say charge $2500 per team minimum. This will price a lot of us out of it, but we're really not the target. The people who can raise the type money we need can afford this. Have two seperate competitions: first, the low score team, and two, the high money team. The low score team gets typical golf related prizes, but the high money team gets a free game in a luxury box at BDS in the fall, pampered in the style they deserve. The teams can canvas anyone they want to help donates, and those funds go directly to GTAA.