Bets are offered on a series of coin flips. Details have been added for this solution. 
- The sequence HTT will appear before TTT.  If it does, I give you $1. If not, you give me $4. (Good for you. Cost = .80, Expectation = .84)
- The sequence HHT will appear before TTT.  If it does, I give you $1. If not, you give me $3. (Bad for you. Cost = .75, Expectation = .69)
- The sequence THH will appear before HHT.  If it does, I give you $1. If not, you give me $2. (Good for you. Cost = .67, Expectation = .70)
- The sequence HTH will appear before THH.  If it does, I give you $1. If not, you give me $1. (Good for you. Cost = .50, Expectation = .51)
The graphic below shows how the coin flip sequences compare. Code for generating these images is at the 
Coin Flips demo at the 
Wolfram Demonstrations Project. Recreational mathematicians can use this 
code in the newly released 
Wolfram Mathematica Home Edition. Previous
puzzles are archived at the 
Math behind Numb3rs Season 5 page.