When something is nothing/invaluable for a goal, it means that you sacrifice it easily in the way of achieving your goal.
In my example "freeing people" is his goal. and "world" is all his belongings and materials. So he is ready to sacrifice all his world and all his pleasure to free people.
"Invaluable" does not mean "not valuable," as you seem to think it does. Rather, it means "so valuable that its true value cannot be determined" -- in other words, "very valuable."