Tangible incentives have a bad reputation for encouraging the worst behaviors.
This is partly well-deserved. Tangible incentives are great when people had little interest in performing that behavior in the first place, but beyond that, they can cause more problems than they solve.
Tangible incentives (like money) are best used as part of a properly designed system. Three good options here are prize bounties, raffle systems, and tipping.
Prize bounties are when someone sets a reward for the person(s) who provide the best-accepted solution to a challenge. However, if the odds of winning are too low, why participate? It’s best to distribute the prize and offer the chance of random rewards for specific, smaller, activities. LocalMotors’ LaunchForth does this well.
Another option is the raffle system. We use a variation of this in our online community. Each month, people are allocated ‘tickets’ based upon the number of accepted solutions they’ve contributed. At the end of the month, a draw is made and the winner gets the prize. You are more likely to win with more good contributions, but it’s not guaranteed.
The final system is as a tipping system. Each member is given $x per day they can use to tip people who make great contributions. The money expires at the end of the day. Those that don’t tip get less to spend the next time, those that use it get more. Steemit uses a simple tipping system (you can replace money with points, but it’s less effective).
You can figure out the best system for you. Be aware, anytime you create a system with tangible rewards people will try to cheat. But that doesn’t mean you should avoid them entirely. You can get this right.