For $24 you can box 4 dogs, half the field.

I have had 69 races as a test for boxing trifectas and getting some value.

Spent $1656
Returns $2908.40
Profit 76%

Whilst you may think $24 is expensive and if you have 5 loosing bets in a row well there go's $120. But if you win one bet, you would win most of it back. whereas straight out bets you would need a $6 winner to get back even.

With the 69 races, i have had 27 trifectas
thats 37% of selecting a trifecta.

So whilst you spend big buck, you also return big bucks.