Generally people are shy about how much they pay their employees publicly.
It's probably a flat fee.
If I had no other figures to go by, I personally would guesstimate how many hours the tournament
will take. Then figure on paying at a bare minimum ten bucks an hour,
for some random guy who isn't experienced at it running a small tourney.
For a good TD I think that'd be considered a low (almost insulting) offer.