The rich get richer — by shoplifting.

A surprising number of customers helping themselves to five-finger discounts in Manhattan are wealthy — and they feel their big spending entitles them to free stuff, retail workers tell The Post.

Makeup mecca Sephora sees shoplifters sliding lipsticks and perfumes up sleeves — often items the thrill-seeking thieves don’t need or want, like foundation in the wrong shade or a mascara ­tester used by hundreds of people.

“It becomes a cat-and-mouse game: What are you going to see me take today?” said a former Sephora employee, who once busted a yuppie mommy hiding a stolen booty of cosmetics and skin products just behind her baby’s head in an $800 Bugaboo stroller.

Items are often lifted by privileged shoppers who somehow feel they deserve more.

“They’d pay for one of the things they were still holding but drop something extra in their shopping bag, like their own version of a free gift,” said the Sephora insider.

At Anthropologie, some upper-middle-class women buy $400 kaftans and $500 clogs — and then “accessorize” for free.

“We were taught that our prime shoplifters were women and girls who were regular shoppers at ­Anthro,” said one ex-employee, who every night would find piles of security tags in the fitting rooms that were taken off apparel that day.

We were taught that our prime shoplifters were women and girls who were regular shoppers at ­Anthro. - Ex-Anthropologie employee

“They would spend insane amounts and at the same time steal a few items because they felt that given they had spent so much money, they were entitled to freebies,” the Anthro insider said.

It’s often the best customers who steal the most, said a former Macy’s manager.

“They’re spending $100,000 a year . . . Even though he just stole a bag for $5,000,” the ex-staffer said.

Retailers vary in their approach to theft. The ex-Macy’s boss said she was wary of pinching the wrong pilferer.

“It could be a producer, a celebrity, some big-time lawyer,” she said. “So you don’t want to attack them or wrongly accuse them.”

Last week, “Real Housewives of Beverly Hills” star Kim Richards was arrested for allegedly stealing $600 worth of items from a Target in California.

Lindsay Lohan pleaded “no contest” for nicking a $2,500 necklace from a Venice Beach jewelry store in 2011, while actress Winona Ryder was charged in 2001 for stealing $5,500 worth of clothing and handbags — she purchased four items but hid another 20 in her bag and clothes.

Sephora tries to shame thieving customers with dazzling customer service.

“If I saw you take a lipstick and drop it into your purse, I would walk up to you about two minutes after you did that and say, ‘I saw you looking at that lipstick earlier, let me find a really great lip liner to go with that lipstick,’ ” the insider said.

At Intermix, a clothing boutique that stocks Valentino handbags for $2,500 and Narciso Rodriquez cocktail dresses worth $1,500, customers would purchase an outfit for an event and then return it, claiming it was never worn, and demand a full refund — which they would get, in order to keep them happy.

“You can see an armpit stain . . . or it’s full-length and it’s a little bit dirty at the hem line,” noted the ex-Intermix staffer.

“But, the customer is always right, even when they are lying to your face.”