It can be as easy as having that struggling young couple over for dinner, or signing up with one of the missions to children, or donating to the missions fund at your church. There are 6 billion people on this planet and too many of then have never heard the gospel of Christ. This is starvation of the worst kind. While the average American home has 2 to 4 Bibles, believers all over the world have handwritten, carefully-kept texts from listening to short wave stations, if they have that. Many of the world's population are under fed, while we need weight off and diet programs by the score.
Missions can be across the street or on the other side of the world.
But missions is supported by believers praying and giving of their time, talents and giving back this world's goods that God has entrusted us with as stewards. God loves a cheerful giver. If giving is really going to put a crimp in your situation, God knows that too. If you can not give cheerfully, with joy in your heart, I'm not sure God wants you to give. True, we should not use our emotions as a gauge of when to give, or bow to pleading manipulation.