The House Advantage is the expected casino profit per bet.  Or put another way it is the expected amount the average player will loose per resolved bet.

Below are the basic craps bets and their house advantage.  You can easily see the bets that will statistically cost you a lot of money.

Craps Bet	House Adv.
Pass/Come	1.42%
Don't Pass/Don't Come	1.36%
Place 6, 8	1.52%
Place 5, 9	4.00%
Place 4, 10	6.67%
Buy 6, 8	4.76%
Buy 5, 9	4.76%
Buy 4, 10	4.76%
Lay 6, 8	4.00%
Lay 5, 9	3.23%
Lay 4, 10	2.44%
Field (2X on 12)	5.56%
Field (3X on 12)	2.48%
Any Craps	11.11%
Hard 6, 8	9.09%
Hard 4, 10	11.11%
Proposition 2, 12	13.89%
Proposition 3, 11	11.11%
Any Craps	11.11%
Any 7	16.67%

So let's take a quick look to see how much it will cost to play this game if you bet $10 on the Pass Line, and $12 each on the Place 6 and 8.  Let's also say this is a rather slow game with 60 rolls per hour and a decision made every 4 rolls (statistically the pass line and place 6, 8 are resolved about every 3.3 rolls).  So your expected loss per hour would be 15*($10*1.42% + $12*1.52% + $12*1.52%) which equals $7.60.

If you add a $5 Any 7 bet onto that your expected hourly loss jumps to $20.10.