Does your company provide a 401(k) plan for its employees? If it does, you may defer part of your salary via payroll deductions, up to annual limits, and have the funds in your account accumulate on a tax-deferred basis. For 2015, the maximum deferral is $18,000 or $24,000 if you're age 50 or over. In addition, your company may kick in matching contributions up to a stated percentage of your compensation. And there's no tax on earnings within your account until you make withdrawals.