Serena Williams Reveals She's a ‘Boring Spender’: 'I Am Really Bad at Treating Myself'

When it comes to money, superstar tennis champion Serena Williams reveals she likes to spend smart.

“I don’t spend money — when I do it’s on my daughter. I usually invest my funds. I am the most boring spending ever,” Williams, 37, tells PEOPLE. “Don’t spend it, invest it,” she advises.

The tennis star even admits that she’s bad at spending her hard-earned cash on herself.

“I am really bad at treating myself, so I am learning how to treat myself more. I am working on it. I’ve thought about some jewelry,” she says.

But when the S by Serena designer does like to spend her championship earnings, she turns to her essentials — available Wednesday on her brand-new Amazon storefront.

Now Williams’ fans can shop just like the tennis pro by purchasing some of the star’s favorite products through her carefully curated Amazon shop.

“Obviously the Wilson tennis balls are super important to me,” she says of the popular tennis ball brand — just one of the many tennis-themed items shoppers can purchase through the storefront.

“The resistance bands I also use as stretch bands and they are very essential,” she says of the AmazonBasics Pound Resistance Pull Up Bands, before explaining her travel training sessions.

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“We travel with everything in a massive big training bag and we normally just throw a ball in there — I also like my beats headphones which I normally walk onto the court with,” she explains.

“I have a playlist that I always listen to … I try to listen to more motivational music and normally listen to more lyrics as opposed to just beats,” Williams says of her pre-match pump-up.

In addition to workout and sports-related items, such as the Schwinn Indoor Cycling Bike and the AmazonBasics Extra Thick Exercise Mat, the athlete’s storefront also consists of some of her favorite mommy items for her daughter, Olympia.

“Basically, everything from grabbing pampers on our storefront, or different medicines if she gets sick,” Williams says referring to her 2-year-old daughter, who she shares with husband Alexis Ohanian. “One thing I really like is Olly’s, these little gummies for kids. It’s also a company I invested in. I grab them on the go. When it comes to Olympia, she basically has her own account on Amazon,” she jokes.

Williams’ storefront also features some relaxing downtime items such as the TriggerPoint Impact Handheld Percussion 4-Speed Massage Gun and the ProsourceFit Acupressure Mat and PillowSet for Back/Neck Pain Relief and Muscle Relaxation.

And in the midst of the holiday season, most people will be doing more relaxing (and eating) than exercising. But the mother, tennis champion and fashion designer encourages everyone to get up and out in order to feel good and balance out all those holiday meals.

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“I am cheating a little bit because a tennis player winter is training season so it’s a little bit unfair. We always leave around Christmas or Thanksgiving and then go to training camp so I am in the most intense training by the time December comes, but I also don’t celebrate holidays so it’s a double-time for me,” Williams says, noting that while her holiday season workouts are more unconventional, people should still try to find some time to sweat it out.

“I say a half-hour out of your day to go for a walk or a run — it’s really not a lot of time out of your day,” she suggests. “Especially if you are eating a lot during the holidays — and sometimes I think about that during my off days, just go out for 20 minutes on a run, at least three days a week and it makes you feel better.”

Back in October, Williams revealed to PEOPLE that she is looking forward to expanding her e-commerce and fashion empire and one day hopes to create a baby wear line inspired by her daughter.

“I am hands-on in everything I do, and this is no exception,” she said at the time.

And like any working mom, the superstar said she’s just taking everything day by day.

“I basically don’t balance,” she said, laughing. “When I do something one day, it is 100 percent. Then when I am done, I am done and on to the next thing! I live and breathe fashion in the tennis off-season, but no matter what else I do, I am always a mom and I love every minute of it.”

Shop Williams’ storefront here.