Online retailers are changing their prices based on who's shopping.

From American Public Media, this is Marketplace Tech.

I'm Megan McCarty Carrino.

Maybe you've heard of dynamic pricing, where companies change prices in real time based on fluctuations in demand.

Well, some retailers are now using the vast troves of personal data they collect on customers to go a step further.

It's called surveillance pricing, different prices for different

customers. Marketplaces Kristen Schwab has more. Technology means companies know more about shoppers than ever,

but in reality, retailers have always been quietly collecting data on us. It's a practice as old

as commerce itself. Joseph Turrow is author of The Voice

Catchers, how marketers listen in to exploit your emotions, your privacy, and your wallet.

People think that personalization is a 21st century phenomenon due to the internet. It goes back

to peddlers and before. Business owners would keep notebooks on what kind of

clothes you wore or who your friends and family were. The difference is back then, a shopkeeper had to

guess if a woman's baby bump was indeed a baby bump. Now a retailer knows the instant she adds

prenatal vitamins to her cart. It's legal to do it.

And some economists would say that price differentiation is just part of the way that economics works.

But to me, that's problematic.

He says a lot of consumers have no idea surveillance pricing is happening.

How common this kind of practice is, no one really knows.

But retailers are watching us closely, often for surveillance discounting. Here's a coupon for being a member or 10% off that immersion blender sitting in your cart.

It's why, as a consumer, it's more difficult than ever to figure out if you're getting the best price.

Garrett Johnson is a marketing professor at Boston University.

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