Teaching my kids about money the Christian way

Trying to raise my boys to understand that money isn't evil but it's also not the goal in life. I want them to be generous, work hard, and trust God for what they need. But I also live in a world where everyone around us is materialistic and they see that stuff. Taking them to help serve at the homeless shelter on Saturdays and we talk about stewardship but sometimes I wonder if I'm doing enough to actually show them what it means to give sacrificially. Anyone else dealing with this?