A cumulative trophy, though you certainly will find that money is a rare commodity. You will find cents for the most part from the spoils of combat, so the majority of the money will end up from either selling junk (or equipment if you are that desperate) and then spending it again. If you're going for the equipment trophy for owning all costumes and weapons, you'll definitely obtain this trophy along the way (though you'll probably end up spending about double that to get everything. Just concentrate on everything else and you'll see this pop up before you know it.