We went to a Florida JUCO showcase on Sunday and learned a lot. Among the schools that were there, the coaches told us this:
They gave out 18 total scholarships, and they range from tuition, fees and housing to just tuition and fees. One of them had breakfast and lunch included for the 100% guys. A couple of them had no on-campus housing, but gave an allowance. Each one is a little bit different. The one your son is talking with may be different as well, so best for him to nail these things down directly with the coach.
Among these four schools, they carry 32-35 players in the fall, and 23-26 players in the spring. A lot of scholarships go to pitchers. So that means they always have several walk-ons, who they said had just as much of a chance to be starters as the scholarship guys did. The example at Central Florida was a player who walked on last year and just signed with South Carolina. Naturally, they were all big on Bright Futures qualifiers.
All of these coaches seemed very approachable and made it clear that they wanted to hear from interested players.
I agree with floridafan - if they're talking to your son right now, I would expect some money to be offered. If you have Bright Futures and Florida Prepaid, plus a scholarship, you could have a pretty sweet deal.