Complex sentence: If all ten words were guessed correctly in 60 seconds, in addition to winning $250/$500 they also won a car; otherwise, the dollar amount won was redeemed for merchandise from the Spiegel Catalog.
Split into simpler sentences: If all ten words were guessed correctly in 60 seconds, in addition to winning $250 or $500, they would also win a car. Otherwise, the dollar amount won was redeemed for merchandise from the Spiegel Catalog.