Does the potential for financial reward motivate high school students to take their learning more seriously ?

You can do it but only once because if you always motivate them using financial rewards, they can be greedy and passive in learning though it is effective.

Not really. The most famous rich people are those who pretty obviously didn’t take learning seriously. They are performers of some sort–those who are paid for letting us watch and listen to them do whatever they do–actors, sports figures, musicians. Besides, a desire for wealth is seldom satisfied–people almost always want more.

It would be better to have them create scenarios of the kind of life they want as adults and then work backwards from there to what they’ll have to do to achieve it. Some basic knowledge of statistical probability would be good also. If only 1 in a million garage bands makes it to the chartered bus touring level, show your would-be rock star a million things, like pennies, rocks, stars in the sky, or cans at a factory; select one (write it down) and ask him/her to pick it out you chose.