I tell folks to budget a grand.
Our classroom & pool course is $248, which includes books, tables, classroom materials, C-Card & equipment except mask, fins, snorkel & weightbelt. We go to the springs for four dives one weekend, and to the Gulf for two more another weekend. We're far enough away that these weekends entail a night in a motel... with boat fees, food, etc, it all works out to about a grand.
I could do it for $400 using the lake, but it wouldn't be near as much fun, and it wouldn't provide near as much real diving experience - there's nothing like those Gulf dives from a boat and all that the trip entails to produce a diver who's actually ready to go it on their own.
Rick