If privacy is that important to you then just pay cash. Otherwise your credit card company, your bank, Facebook, Equifax, Google and the store itself among others are all tracking you as much as possible across purchases in the physical retail world and across all your web traffic. All of these datapoints are being cross-correlated in a billion different ways.

"I'm not on Facebook" - oh yes you are. There's a shadow profile built of you even though you never signed up for Facebook. Same goes for Google, and many other services you never explicitly signed up for.

So now let's talk about cash. So you pay with cash and you think your privacy is preserved? Nope! The moment you walk in the store, the wifi beacons are tapping into your smartphone and adding to the internal profile the shop has of you. They know when you walked in the store, they know when you walked out, and they probably know enough to correlate your cash payment with your profile.

I'm sorry but that's the world we live in.