Here are some options Immigration Planner put together to help sponsors meet their financial obligations.
The sponsor uses his or her assets to bridge the gap between his or her income and the financial obligation. $15,000 of assets is the equivalent of $3,000 of income ($5,000 if the sponsor is a U.S. citizen and the applicant his or her spouse or children 17 years old or younger)
The sponsor asks household members to join him or her in sponsoring the applicant by combining their income.
The sponsor asks a person who is not a household member, the joint sponsor, to join him or her in sponsoring the applicant.