In the US the highest award for military valor is the Congressional Medal of Honor, presented by the President. This medal was awarded to combatants in both WW I and WW II
During his service in World War I, Hitler attained the rank of Gefreiter, which is often translated as corporal. It's about equivalent to Private First Class in the US Army.
If the badge you have is the same as the one here, wargamming.com then it is an Expert Rifleman Badge. It was obsolete by World War Two, but many who won it previously still wore it during the war.
$5 see ebay
Minesweeper War Badge was created on 1940-08-31.
Destroyer War Badge was created on 1940-06-04.
About $200-500$ depending on condition
$10 try ebay
U-boat War Badge was created on 1918-02-01.
Naval Artillery War Badge was created on 1941-06-24.
80%
Downfall
There are many high grossing movies about World War Two. The highest grossing World War Two movie is called "Saving Private Ryan", which received eleven Academy Award nominations.