Three Dice Rolls

Three Dice Rolls
StrategyMedium

A casino offers a dice game where you can roll a fair 6-sided die upto 3 times. After each roll, if you get a number x, you win $x. After the first or second roll, you can choose to either keep your winnings or continue rolling - but if you continue rolling, you forfeit the current amount. If you make it to the third roll, you must accept whatever amount you roll and the game ends.

What is the game worth and what is your strategy?