是鼓勵低收入人士為退休存錢。此壇這類的不多吧，除了學生

http://www.irs.gov/newsroom/article/0,,id=107686,00.html

The Retirement Savings Contributions Credit applies to:
• Individuals with incomes up to $25,000 ($37,500 for a head of household) and married couples, filing jointly with incomes up to $50,000
• You must also be at least age 18, not a full-time student and you cannot be claimed as a dependent on another person’s return