I went with Derick at http://phatfishkayakcharters.com/
for a half-day when I was in St. Petersburg, FL earlier in the year. According to his website rate is $ 150/half day. I think that is low considering he has to bring his kayaks, fishing gear, etc.
I didn't catch too much probably based on my lack of skill, rather than the guiding but learned a little about staking the boat in shallow water. Kayak was really stable SOT.