The meanings are the same IF you can understand them! Your first sentence --
Half as much money as total national income was wagered in the country's betting shops
-- is the most successful, but it doesn't tell us whose national income. If we add that information --
Half as much money as the country's total national income was wagered in its betting shops
-- the reader has to wait a long time for the first verb (was wagered).
Your second sentence, as I think you suspect, shouldn't begin 'Money Half'! As KB suggested, dashes or brackets might help, but again we need to know whose national income. So:
Money - half as much as its national income - was wagered in the
country's betting shops.
or
Money - half as much as the country's national income - was wagered in its betting shops.
Those are quite good. And you got rid of the redundant 'total'.
These would be more concise:
Money equalling half the country's national income was wagered in its
betting shops.
Or
Money equalling half its national income was wagered in the country's betting shops.
By the way, you could replace "equalling" with "equivalent to", if you wished. And you could spell 'equalling' 'equaling' if your readers were in the US.