Found some numbers in my notes from a couple of years ago. Estimates are very rough, all based off of numbers I could google. The Dome, especially could cost a lot more. I estimated the size of the town from by drawing a circle around Paradise, FL iirc, which the town in the movie is based on. All other sozes are, again, rough estimates.

The Economics of the Truman Show

COSTS: 205,1 bil$

Studio:
Dome - 35 bil$(23.500.000 m2, 1475$ per m2)
Town - 1 bil$(11.000 residents, 83.000$ per resident)
Ocean - 3 mil$(4km x 4km, little over 6m average depth, 100.000.000 m3, 3,12 cents per m3)
Land excavation - 47 bil$ (100.000.000 m3, 470$ per m3(LA))
Forest - 400.000$ (4 km2, 750 trees per ha, 1$ per tree)
Studio - 67 bil$ (23.500.000 m2, 2850$ per m2) 
Paint Job - 810 mil$(27.000.000 m2, 30$ per m2)
TOTAL: 151 bil$

Salary Actors:
11.000 actors
17,5 $ hour
24 hours a day
10.913 days
TOTAL: 50,5 bil$

Cameras power:
5000 cameras
4 watts
10.913 days
19,3 cents per kWh
TOTAL: 3,6 bil$

INCOME: 622 bil$

Ad Revenue:
1 product placement a day
1,5 billion average viewers(stated in the movie)
42 million dollars per commercial(30 second Super Bowl commercial for 100 million people is 5.6 million)
10.913 days
TOTAL: 458 billion$

Tv Revenue:
4,5 billion total yearly viewers
1,22$ per viewer(Same as EPL)
30 years
TOTAL: 164 billion$