Laying The Odds
When you're talking about Craps the DON'T Pass and DON'T Come bets, things are a little different, in that instead of TAKING odds, you are going to be LAYING odds. That's because rather than betting on any one number being rolled BEFORE the seven - the most common number - is rolled again, which puts the odds against you, you are actually betting on the seven being rolled BEFORE the point is rolled again. That means the odds are in your favor.
But once again, you are going to be dealing with true odds. So on the 4 and 10, with your $20 odds bet you are going to be laying $20 to win $10. If the seven rolls before the four or ten, you will win $20, which is your Don't Pass bet plus your odds bet at even money.
Odds for the "Don't" bets are like a reverse - think of it as if you put the odds up in front of a mirror. If the 5 and 9 are 3-2 on the Pass, they are 2-3 on the Don't pass, and so on.
Along similar lines, you can LAY odds that the point will not be made before the seven is rolled. This is done through the LAY BET, which can be made at any time. Once again, you're going to be laying odds here, because in the gambler's language, you have "the best of it."
Of course the casino knows this. It also knows that since you can put down the lay bet at any time, as someone who aspires to be a smart player, you are likely going to be tracking the dice and jumping in with that bet when the "law of averages" is in your favor (of course, we know the dice have no memory, but that's been covered already).
Therefore, the casino is going to make you pay a "vig" (or commission) when you make this kind of bet. You will generally pay only on the potential win, though the casino is not sitting back and waiting for the result to collect. Let's illustrate this as easily as we can. Let's say you are going to "lay" $40 that the seven is going to be rolled before the point of 10 is made. You are laying 2-1 odds, meaning the potential win with that is $20. The casino will take $1 from you as the non-refundable commission, which constitutes 5%.
Oh yes, by "non-refundable" we mean that the casino still takes the commission even if you lose the bet.