Here's an idea: addictive substances
Make the cigarettes cost $10 a pack (It's up that high in some areas
) and have them improve the accuracy of the person, at the cost of 5 hp (temporary). Then, make it so that if they smoke more than 3 a day, they will lose hp if they don't keep it up.
Better than making them an event prize.
You could do that for other substances too. Steroids, for example. Side effect: possible roid rage shooting frenzy.
Be creative, you need people buying stuff constantly. Increase the price on ammo too. Everyone needs that. Keep handgun ammo, shotgun, uzi, etc cheap, so noobs aren't hurt by it too much, but increase everything else. And btw, you can tax income. Just do it through the banks or something.
Might want to do something soon though, some people have been complaining.