If you routinely shop online without going through a cashback portal, you could be missing out on some significant savings.

How would you like to get up to 40% back on almost every purchase? With Cashback sites, you can. The following rebate programs are free to join and offer sign-up bonuses to new members:

• Ebates – receive $10 bonus when you join today
• Top Cashback – new members get $10 cash for signing up
• Giving Assistant – new members earn a $5 bonus
• Mr. Rebates – get a $10 bonus for signing up
• BeFrugal – new members receive a $10 sign-up bonus

How do Cashback Sites Work?

Cashback sites use referral links to connect you with the stores you wish to shop and receive commissions for doing so, which they then share with you in the form of cash rebates.

Most cashback sites make money by keeping a small portion of these referral fees and passing the remainder along to their customers. What they lose in percentage points, they make up in volume — a win-win for all concerned.

Other sites, like Top CashBack, give 100% of their commissions back to their customers. They make their money through advertising and other affiliate bonuses.

How Do Cashback Rates Compare?

Cashback percentages vary by site, by store, and even by day of the week. A site that offers the highest percent back at one store may have the lowest rate at another store. Another that offers 4% back at one store today may offer 12% at the exact same store tomorrow. To illustrate this wide variability, I recently compiled a chart showing the different cashback rates offered by several leading cashback sites at about three dozen popular merchants:

As you can see, rebate percentages are all over the map. You could check each of the sites for the best rate before making any purchase, but of course, that would take time. It may be worth it to do that on big purchases, but I think “some” is better than “none,” so for convenience’s sake, I normally just pick one rebate program and stick with it.

How Do You Choose a Primary Cashback Site?

In addition to rebate rates offered, you will also want to consider other features cashback sites offer. Here again, I thought a chart might help you make side-by-side comparisons and pick the features most important to you:

• Ease of Use

  It doesn’t matter how high the percentage rates offered, if a site is cumbersome and difficult to use, you probably won’t. That’s why I highly recommend choosing a site that allows you to install a browser button that will automatically alert you about available cashback everytime you make a purchase. One click, and you get the cash. How simple is that?

• Frequency of Payout

  This varies from site to site, too. Some people want to get their money as soon as it’s available and don’t mind the fact they have to request payment every time. I like having the money automatically deposited without my having to remember to claim it, and it doesn’t matter to me that payments are only made quarterly.

• Minimum Payment

  If you don’t shop online very often, you might want to use a program that doesn’t require you to amass a large rebate before granting you access to the money. Although not listed on this chart, method of payment may also be something you’ll want to research. Most sites will pay through PayPal, but some offer other ways to access your money or give you the option of donating all or part of your savings to charity.

• Participating Merchants

  Each site varies slightly in the number and types of merchants that participate in their rebate program. If there is a particular store you shop frequently, you’ll want to make sure the rebate program you choose offers cashback for purchases made with that particular merchant.

• Program’s Reputation

  Obviously, it doesn’t matter how high the cashback percentages promised are if the company doesn’t follow through with payment, so you may want to check out a company’s ratings and reviews before committing.

Which Site Do I Recommend?

I have a good friend who’s enjoyed great success using Giving Assistant, but the only rebate site I can personally vouch for is Ebates.

I’ve been using Ebates for nearly 20 years. I’ve earned thousands of dollars in cashback doing so and have never once had a problem with disputed claims. The higher percentage rates other sites offer look tempting, but Ebates has been a sure thing for me for so long, I’ve opted to just stick with the bird in my hand.

Ebates fits my lifestyle, and even offers cashback on in-store purchases for a growing number of restaurants and businesses, some of which I shop routinely. Winning!

I never have to remember to request my rebate. The money I earn just “magically” appears in my PayPal account once a quarter (although they do give members the option of receiving payments early — with a bonus — if they’ll opt to receive a gift card instead of cash).

I’ve installed the Ebates cashback browser button on every computer in our house. The button lights up every time any of us try to make an online purchase for which cashback is available. One click on the button activates the rate, then we check out as normal and enjoy the extra savings without having to hardly even think about it.

Several other sites now offer the same kind of browser button as Ebates. I’ve tried installing those on my computer, too, thinking it would allow me to compare and choose the best rate for any given purchase, but they really don’t work as reliably when you use more than one. So now I’m back to using only the Ebates button. For a step-by-step instructions on how to install an ebates browser button on your computer, watch this short tutorial:

By way of explanation, the “Big N Marketplace” listed above is a program only available to Team National members. I included them in my comparison because their rates used to be some of the highest available. Unfortunately, their website is not as user friendly as many of the others listed and the cashback percentages are not as consistently high as they once were, so I wouldn’t join solely for the sake of accessing the marketplace, as it makes better sense to just use the free programs.

If, however, you plan to make some bigger purchases in the near future, Team National might be worth investigating. My husband and I bought a lifetime membership a couple years ago as a way of saving money (beyond the stated cashback percentages) on new cars and home furnishings. We were moving into a new house at the time and also buying cars for kids leaving for college, and the discounts we got in those categories more than covered the cost of our membership.

UPDATE: Since publication, I’ve learned of an additional cashback site called Lemoney. They offer competitive rates, as well as “turbocashback” at over 1500 stores. That’s all I know, but if you are a die-hard comparison shopper, you may also want to check them out.