dollars to doughnuts
A Comparison of something with worth to something without. Originated in ages past when doughnuts were extremely cheap. Chiefly used as a comparison for odds purposes as in the example.
Party A Betting "100 dollars to doughnuts" against Party B would pay a winning party B 100 Dollars, versus 100 doughnuts (vastly cheaper than one hundred dollars) paid to a winning Party A.