It’s hard to shop (or eat) anywhere these days without being given the opportunity to join a customer loyalty program. From simple paper cards that get a hole punched in them each time you buy a sandwich, to bar codes, magnetic strips and RFID devices that track every purchase you make, frequent customer programs are an essential part of many companies’ marketing efforts. If you’re willing to offer up a little of your privacy, they can also be an essential part of your own efforts to get some of the .

Nearly three-quarters of all shoppers in the United States now belong to at least one loyalty program. Companies typically design these programs to reward, and therefore encourage, loyal buying behavior from customers.

These days, "advantage cards" or "rewards cards" usually have a bar code or magnetic strip that can be scanned when you checkout. They may offer discounts on particular items immediately, or reward certain purchases in other ways. For instance, a supermarket may give you a free gallon of milk after you purchase nine. Or you might accumulate points with your purchases that can be redeemed for gifts or credits for use in the store.

It makes sense if you’re already a "loyal" customer of a particular firm to take advantage of these discounts. It generally takes a minimal amount of time to sign up for the programs, and the personal information they collect from you is fairly limited as well. Do be aware that although information about your own individual shopping behaviors shouldn’t be disclosed to other organizations except in the aggregate, it may be used to "optimize" offers made to you. In other words, if you routinely purchase certain brands or items, the firm might market certain similar or complementary items to you. Depending on the program they may also send you information by mail or email. If you have concerns about collection and disclosure of personal information or have objections to receiving offers by mail or email make sure you read the disclosure statement for the program before signing up.

In addition to rewards programs for individual firms, you might also want to check out some of the online programs available such as or . There are even rewards programs that allow you to make donations to charity. Don’t forget the "earn back" provisions available from many credit card companies.

As with other opportunities for savings, you’ll want to make sure you understand the rules of any particular rewards program before you sign up, and only shop or use rewards for things you actually need. Since most firms see a rewards program as a normal cost of doing business, you’ll likely find one that will save you money on many of the things you’re already buying.