https://www.playstationtrophies.org/...-of-Money.html

Sony has offered an interesting update to its Rewards Program, currently enabling players (in the US only, at present) to earn small amounts of cash for unlocking PlayStation trophies. Any new PS trophies you unlock (there are no retroactive rewards) will earn you points, that can in turn be traded for money credited to your PSN account.

For 1000 points, you can get a $10 voucher, which equates to unlocking ten platinum trophies, 100 gold trophies or 1000 silver trophies. You get absolutely bugger all for lowly bronze trophies, other than the warm sense of satisfaction that comes with that little trophy 'ding' when it unlocks.

If, like me, your maths is a bit rusty, the breakdown is thus (as per the image above): 10 platinum trophies garners 1000 points (obviously), 25 gold trophies nets 250 points, and 100 silver trophies earns 100 points. To take part in the Sony Rewards Program and start putting your trophies to work, you can sign up here (again, it's currently US only).
Awesome, I already gained some points since this started and I got a huge backlog of games to play.