Terri Gault has one rule when she shops.
"I just can't stand to pay full price, and I won't," she says.
She describes herself as the queen of cheap.
She took Early Show national correspondent Tracy Smith along to Ralph's supermarket, where she saved a bundle.
She spent $11.61 for what would normally cost $49.06.
Then at Staples, she paid 44 cents for $28 worth of office supplies.
And who says there's no such thing as a free lunch?
At Toys R Us she got a whole bike for free.
How did she do it? As the founder of an Internet shopping site called "The Grocery Game," she knows her way around coupons. But the real bang for the buck comes from joining customer loyalty and reward programs, which nowadays seem to be everywhere.
"I think that we've been programmed to expect loyalty or reward of some sort because it's a huge marketing trend right now," Gaul says. "Everybody's doing it, and if you're not doing it, you're probably not up to speed."
So holiday shoppers now expect not only to give, but to receive something in return. Three-quarters have joined loyalty programs — racking up airline miles, getting free shipping, free dog food, clothing discounts — all efforts by businesses to keep customers coming back.
Even a trip to the doctor can be rewarding. In New York, Maria Sierra stopped in for an injection of Restylane to smooth things out around her nose.
For every treatment she buys, about every 6 months, she not only gets fewer wrinkles, she gets a gift card to a store like Nordstrom's.
But why does she need a rewards program if she is happy with the treatment and would do it anyway?
"I like to save," Sierra says. "I got the card, I got wonderful savings. I like to save, I work hard, it's a good thing."
The man at the other end of the needle is Dr. Michael Kane.
Smith tells the doctor she was shocked when she first heard about a rewards program for Restylane, for something that a plastic surgeon offers.
"Right. But, I mean, plastic surgery things are becoming more and more mainstream," Kane responds. "I mean, this is a medical procedure. But more and more to people in the public, it's — it is almost like going to the mall and getting a nice gift for yourself."
You can trace it all back to programs like Gold Bond Stamps, which started in 1938. Grocery stores gave out stamps based on how much you spent. Then you redeemed the stamps for free stuff.
"I remember wanting ice skates for some reason and got ice skates from the Gold Bond Stamps," says Marilyn Carlson Nelson, the daughter of the founder of Gold Bond Stamps, Curtis Carlson.
Now she's the CEO.
And Gold Bond Stamps have turned into the Gold Points program, with 11-million members. The concept hasn't changed. Build up points — get free stuff.
"Sometimes people think that if they offer cash discounts, that that's very powerful," Nelson says. "But there's something aspirational about saving for things that you particularly want."
Do the points have more power than cash, more power than discounts?
"We actually believe they do," Nelson says.
At Petco pet stores, they believe discounts will keep the members of their P.A.L.S. program loyal. But there's something else that drew Smith there. Because if you want to understand the psychology of reward systems, you might want to take a look at… rats.