By contributing to any of these plans, you will build a nest egg and lower your tax bill. By Cameron Huddleston, Former Online Editor April 5, 2010 I have had an IRA for years (since I left Kiplinger's as a full-time employee and became a contract worker). But as my husband and I estimated our tax bill for 2010, we realized we could save big on taxes if I contributed to other types of accounts, rather than limiting myself to the $5,000 contribution limit on my IRA.But what retirement-plan options are there for self-employed people other than an IRA? Plenty. And contributions are tax deductible. Solo 401(k) Maximum contribution: Up to $16,500 plus another 20% of your self-employment income (defined as total business income minus half of your self-employment tax) -- or 25% of your compensation if your business is incorporated -- for a maximum of $49,000. Best for: Someone who wants to maximize contributions to a tax-deferred retirement plan and has no employees other than a spouse. If a spouse works for the company, he or she can contribute up to $49,000, too. Advertisement For a general idea of how much of a contribution you could make based on your self-employment income, use this calculator for a more precise amount. The 401khelpcenter.com has a list of financial firms now providing solo 401(k)s. SEP IRA Maximum contribution: Up to 20% of your net self-employment income , for a maximum of $49,000.There's no additional salary deferral, so your income must be at least $245,000 before you reach the $49,000 contribution level. Best for: High-income business owners who want to maximize contributions through an uncomplicated plan with low fees. You can open and fund a SEP up until your tax filing deadline through a bank, brokerage or mutual fund company. It's easy to set up, and fees are relatively low (less than $100). With the exception of the higher contribution limits, SEPs are subject to the same rules as a regular IRA. SIMPLE Maximum contribution: $11,500 (or 100% of income, whichever is less) a year, plus 2% or 3% of income. Advertisement Best for: Someone with self-employment income -- particularly from consulting or freelance work -- of $30,000 or less. There's no percentage-of-income limit, but actual dollar limits are much lower than for other plans. If you earn $30,000, for example, you can contribute up to $12,400 a year if you take advantage of the 3% matching contribution. At that income level, the most you could set aside with a SEP IRA or Keogh (see below) would be $7,500. Plans are offered by banks, brokerage firms and mutual funds. Keogh Maximum contribution: 20% of self-employed income, up to a $49,000 maximum. Best for: Small-business owners who want to provide an incentive for key employees to stay with the firm. A Keogh lets you set up a vesting schedule to encourage employees to stay with your company longer. However, Keoghs have more administrative burdens.