You probably know that you should save money for retirement. You might even have a 401(k) plan at work, ready and waiting for your pre-tax contributions. But if by chance you don't have one of those plans, or can't take advantage of it, fear not -- you've still got plenty of ways to retire comfortably.

Last year, just 40% of American workers participated in an employee-sponsored retirement plan, according to the folks at the Employee Benefit Research Institute. That's not good news; few of us have pensions these days, and most of us need to build our own nest eggs. Worse yet, only 62% of employers even offered a retirement plan in 2009. Millions of people just don't have such plans available to them.

Many paths to prosperity
Fortunately, there are lots of ways to save for retirement. It's true that 401(k)s, related 403(b)s, and their kin are powerful wealth-building aids. You can sock away as much as $22,000 annually in them if you're 50 or older. But they're not your only option.

However you do it, saving and investing effectively matters most of all. If you can save and invest $5,000 per year for 20 years, and it grows at the stock market's long-term average growth rate of about 10%, you'll end up with a not-too-shabby $315,000.

Let's review some of your alternatives to a 401(k).

These vehicles come in two flavors: traditional and Roth. With a traditional IRA, you contribute pre-tax money into an account that grows, tax-deferred, until you retire. Then you can withdraw from the account, paying taxes on your withdrawals. A key benefit is that your contribution reduces your current income, lowering your tax hit for the year in which it's made.

With a Roth IRA, you contribute post-tax money, so you don't get any tax benefit up front. But your money can grow for many years in the account, and when you withdraw funds in retirement, you'll do so tax-free! (... Assuming that you play by the rules and our government doesn't change the rules along the way.)

You can contribute as much as $5,000 annually to an IRA, or $6,000 if you're 50 or older.

Regular brokerage accounts
You don't need a retirement account to invest for retirement -- nor do you need to be rich to start your own brokerage account. A few hundred dollars is all you need at some brokerages, and a few thousand at others. You can buy as many or as few shares as you can afford. (Just be sure you're not paying more than, say, 2% in trading commissions. If you buy $100 of stock and pay $10 do so, you're already down 10% on the investment.)

Most brokerage accounts let you can buy and sell stocks, ETFs, and even mutual funds. If you go with funds, be sure to check out their fees before investing. A 5.75% load will lop $173 off of a $3,000 investment. Most funds with up-front costs like these (or high expense ratios, aka annual fees) aren't worth the expense, especially considering the multitude of high-quality, low-cost, no-load funds available.

If you're only interested in mutual funds, you can generally invest directly in most funds through their respective companies. So if your brokerage doesn't offer the fund you want, you may be able to download a new-account form from the fund family online and mail it in with a check.

Take action
However you do so, it's vital that you take your retirement into your own hands. Socking away just $5,000 per year won't be enough for most people, and for many, the old standard of 10% of your income isn't enough, either. Take some time to figure out how much you'll need in retirement, and how you'll get there.

If you have a 401(k) plan at work, make the most of it, especially if your employer chips in matching contributions. And given all the different investment vehicles also available to you, your best strategy might be to use several of them.

We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Longtime Fool contributor Selena Maranjian does not own shares of any companies mentioned in this article. The Motley Fool is Fools writing for Fools.