It's a Heart Issue

When it comes to giving money it's not a question of 'how much' but instead 'how'. The way we give our money is more important than the amount that we give. Jesus brought up this point when he was teaching his disciples (Mark 12:41-44; Luke 21:1-4)
when he mentioned how even though the Pharisees gave a lot of money they did not give generously from the heart but only a small amount of their wealth (which seemed to equate to a lot of money) they also were very boastful about it and showed off a lot. However, the widow gave generously and sacrificially and humbly, she gave a couple of coins that were worth very little but she did it with a generous heart and without wanting to show off.

Likewise with our giving it is the heart matter that is the most important, if you can only afford to give $2 a week then start giving that $2 because when you are entrusted with greater wealth you will have the right heart attitude to manage it. Do not wait to be generous until you have enough because the temptation to keep building up a fortune might be too much. As the quote goes - 'Start as you mean to go on'. 

If you cannot commit to a long term project - such as child sponsorship, consider donating to a general fund for disaster relief, or unsponsored children. Also, try and see if you can give up on something so that you can change someone's life, perhaps by giving up doing as much shopping or eating out or even something like not having internet?

The most important thing is that you give from your heart and give from an overflow of all the blessings you have received, even though bigger amounts are useful God values each and every contribution no matter how small and he values the reason behind it the most.