The simplest way to start a 401(k) plan is through your employer. Many companies offer 401(k) plans and some will match part of an employee's contributions. In this case, your 401(k) paperwork and payments will be handled by the company during onboarding. If you are self-employed or run a small business with your spouse, you may be eligible for a solo 401(k) plan, also known as an independent 401(k). These retirement plans allow freelancers and independent contractors to fund their own retirement, even though they are not employed by another company. A solo 401(k) can be created through most online brokers.