2 to 1 on your money
 

Hi,
Often on TV, you see a player go all-in preflop and another player calls with a marginal holding such as K8, TJ, 22, etc because they are getting "2 to 1" on their money. Does this mean that you should call an all-in preflop (as long as it doesn't risk your whole stack and there is no chance of someone re-raising behind you) whenever you get 2-to-1 odds?

IE:
at 100/200, I am on button with a stack of 3000 and there are two limps in front of me, I limp on button w/ 72o(I would never do this but lets say I did) total pot size is 900 now. SB folds and BB has 900 left after posting BB. BB pushes the rest in. Folded to me so I am faced with a decision of calling 900 to win a pot of 1800. I am getting 2-to-1 odds, thus I am supposed to call. Is this correct?

Re: 2 to 1 on your money
 

You might need closer to 3-1 with 72o against a raiser, but with the other hands you mention, K8, TJ, and 22, I would probably call.

Re: 2 to 1 on your money
 

getting 2:1 on your money means that you need to win 1/3 to break even. 32o is 32% to win against a random hand, and when somebody makes a raise preflop you need to recognize you're more likely to be in bad shape.

but say you're the SB at the 50/100 level, and the BB has 50 left after posting 100. then you're basically getting 2:1 b/c you'll put in 100 to win a total of 300, so you should push with any 2, except possible true horror stories like 32 and 43 (you're up against random cards).