There are a number of alternatives to a 401(k) plan for those who are not covered by one through their employer. These include an IRA (both Roth and traditional), a SEP IRA, and a solo 401(k) for those with self-employment income, a taxable investment account, and an HSA account if you are covered by a high deductible health insurance plan. Many of these accounts can be used in conjunction with other options on this list.