3 online sellers who have made thousands of dollars through side hustles: Here are our top tips

"Collectibles are one of the most popular items on" eBay.

Aleah Mazyck.
Courtesy Aleah Mazyck

As a result of the coronavirus pandemic, many Americans are considering picking up a side hustle. More than two-thirds (70%) of Americans say they are considering adding another source of income to become financially stable, according to a recent survey of 2,006 adults by the The National Association of Personal Financial Advisors.

One of the most popular potential side hustles: selling items online, which 37% of respondents said they want to try. There are many sites on which you can list items for sale, including eBay, Mercari, Poshmark, and Facebook Marketplace. And there are some good tricks to ensure you capture the customer base that's really interested in what you're selling.

Here are three tips from successful online sellers about how to grow that kind of side hustle.

Know your clients

Eighteen-year-old Matthew Fiore started selling LEGO online from his own collection when he was 14 years old. "I've been building with LEGO ever since I was young, about 4 years old," he recently told Grow. He'd amassed a large collection of pieces, some of which he didn't mind getting rid of. He's since grossed more than $30,000 selling LEGO online.

Fiore's top tip: Know your clientele. As a lifelong LEGO fan, Fiore is deeply embedded in the LEGO-loving community and knows what buyers are interested in.

For example, "everyone loves Stormtroopers," he told Grow, but the minifigures only come in packages with other items in them. Fiore buys the typical sets, takes them apart, and sells the Stormtroopers alone in packages of anywhere from 20 to 100.

Fiore with some of his Lego.
Courtesy Matthew Fiore

Pick the right platform

Daniella Flores is a side hustle aficionado, with nine side hustles of her own. One of them, selling used guitars on eBay, has brought in $750 to $3,000 a month.

Once you've figured out what you want to sell, do a Google search to see which platforms see the best audience for that item and pick accordingly. While some items may have platforms clearly tailored to them, like secondhand clothing for Poshmark and used tech for Swappa, others may require a bit more research.

"Collectibles are one of the most popular items on" eBay, Flores previously told Grow. Items that fall under its collectibles category include comics, stamps, and sports memorabilia, for example. Flores recommends looking into selling items like records and old china there as well.

Make sure your store reflects you

College student Aleah Mazyck started selling secondhand clothes on Poshmark in her freshman year and quickly realized it was a great, fun way to make money. She's since sold more than $30,000-worth of clothing on the platform, with no plans to stop her side hustle in the future.

One piece of advice she gives: Have your store reflect you. That lets customers know what they can expect and hooks people with similar taste.

For example, Mazyck loves the clothing brand Lululemon. She throws "Lululemon parties," when she releases 30 to 40 items from the brand in her store in one fell swoop. She'll let her 6,000-plus Instagram followers know about the "party" ahead of time so they can prep, which often means those pieces sell quickly. Lovers of the brand know even in the future, if they're looking for Lululemon pieces, she's likely to have some.

Aleah Mazyck.
Courtesy Aleah Mazyck

If you're interested in diving into ongoing e-commerce activities like the above sellers, keep in mind that it may well take some upfront investment. You may need to look for those items and purchase them. You'll also probably have to market your inventory, which may entail spending time on social media to grow a following and let people know about your activities.

Depending on the platform or app where you sell products, there are often processing fees once you make a sale. And you may be responsible for covering shipping charges. Make sure to read through the sites to know how much you could make if you elect to sell on them and price items accordingly.

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