Keith Lango rounded up this interesting information.
When WB took over the studio from Schlesinger in 1944 there was a schedule of 5 weeks for a 7 minute film from start to finish. They had 3 production units with a director and crew for each. Each unit was expected to make 10 shorts per year, or 30 per year for the whole studio.
From the Animgraph site:
1946 WB's Great Piggy Bank Robbery had a production budget of $25,000 (roughly $170k in today's money)or a modern equivalent of $410 per second.
Disney's 1941 Pluto Short Lend a Paw cost roughly $720k (in today's money) for a per second cost of $1700. The same cost applies to any typical MGM 1940 Tom & Jerry short.
1944 Walter Lantz Woody Woodpecker short cost approx. $290,000 in modern money, for a $700 per second cost.
For reference and comparison:
A typical Pixar/Disney/DW/BlueSky film costs approx $15,000 per second for a feature. Theatrical shorts are the same cost. DVD only shorts are about half that. A typical cable TV kid's cartoon show costs about $133 per second (for a 22 minute show). A typical direct to DVD feature costs about $800-1300 per second, depending who's making it.
So from a budgetary standpoint a typical WB 1940's cartoon fell inbetween a modern kid's TV show and a direct to DVD budget.