These plans take many forms, including money purchase plans, profit-sharing plans, employee stock ownership plans, 401k plans, 403b plans, cash balance plans and target benefit plans. None of these guarantee a specific benefit after retirement, but they do specify contribution limits and ensure that at least some money is set aside to grow for after retirement. The same kinds of tax-deferred accounts are available to freelancers, but it's up to each individual to open an account and set money aside. In most cases, you contribute pretax money, meaning you also reduce your current taxable income. The contributions you make to your IRA grow tax-deferred, which means you don't pay any taxes until you withdraw funds.
Contributions are also tax-deductible in most cases.
Unlike a traditional IRA, you do have to pay taxes on the money you contribute. Remember though, you don't have to pay taxes on the money you earn on your investments once you've retired. This is considered a particularly good option for younger workers. Simplified Employee Pension IRAs are designed for sole proprietors and those with any self-employment income. Employers contribute, and employees can elect to contribute if they wish.