The quickest way to become disillusioned with a purchase is to base it on the seller's offer of some attractive perk. The deal hardly ever ends up being as attractive as you think it is.

A case in point is that tempting credit card offer. Consumers have begun to see solicitations from banks offering triple miles and rewards programs with airlines and hotels. How can they be doing that, you ask, since the new credit card law has severely cut into their interest income?

Exactly. The Wall Street Journal recently noted that most of these "high-perk" cards now carry an annual fee. Of course, if the card already has an annual fee, the fee on the new card is higher. For example, Barclays PLC is currently marketing a new "Visa Black" card with 24-hour concierge services. The annual fee is $495.

Keeping in mind that businesses don't become profitable by giving things away will usually help a consumer avoid a bad decision such as falling for a "free" of "trial" offer. The offer always comes with multiple strings attached and usually enrolls the consumer in an on-going "membership" program that will hit his credit or debit card each month.

Be especially leery, for example, of a company that says it will give you one of its products free because it is so confident you will like it, that you will buy more of the product.

Quick way to go out of business

No enterprise could stay in business very long doing that. Odds are they would attract only people who want something for free and have no intention of ever buying a product.

The marketer's real motive becomes apparent when you discover the product isn't really free. You are required to pay a small fee -- sometimes just $2 -- to cover shipping and handling. And of course, you must pay the small fee with your credit or debit card.

Once the company has your credit or debit card, they can place other charges on it at will, leaving it to you to dispute them. Even if they explain to you that you are enrolling in a "trial" program, they are ultimately in control because you've turned over access to your credit or bank account. If you cancel the trial in a timely manner, they can always say you didn't cancel quickly enough.

One way to test whether a product is really "free" is to tell the marketer that, instead of paying by plastic, you will send them a money order for the amount requested. No marketer would accept that, since it would prevent him or her from charging you more later on.

In the midst of a recession it's tempting to be swayed by promises of something for free, since everyone is trying to save money as much as possible. But recognizing the truth in the cliche's "there's no free lunch" and "you get what you pay for" will help you stay out of trouble.