Chances are, we are now seeing more choosing beggars on the Internet than, possibly, ever. With the pandemic and changing consumer habits, the second-hand market is booming. In Spain, for example, 60 percent of people admitted they favor buying used products and giving them a second life. This includes clothes, furniture, and any other products that can be reused, recycled, and upcycled.

In the European country, star products last year were clearly linked to the new situation we find ourselves in, with the sale of second-hand computer monitors, office chairs and desks, exercise bikes and consoles seeing a 23 percent rise in sales.

Furthermore, experts estimate that the second-hand market (especially clothing) will continue to grow in the upcoming years as well. Resale is expected to overtake the traditional thrift and donation segment by 2024.

"For all the challenges Covid posed to our assumptions about consumer behavior, one thing is clear: consumers everywhere are prioritizing value and accelerating the shift to thrift," Anthony S. Marino, president at thredUp, an online consignment and thrift store where people can buy and sell high-quality secondhand clothes, said.

"When times get uncertain, we all focus on our family balance sheet. Brands whose core proposition delivers value and convenience have the opportunity to gain share. Amazon, off-price, and resale are emerging as winners."

However, if you aren't afraid of encountering a few choosing beggars and are willing to sell some of your stuff online, there are plenty of options you can choose from. 

As Stephen Layton and Laura McMullen pointed out on NerdWallet, the major players are Amazon and eBay. But they also have higher fees. On the plus side, they're also some of the most highly-trafficked sites on the Internet. So if speed of sale is your goal, these sites are the way to go. 

You can sell pretty much anything on Amazon, although listing your items in some specialized categories requires Amazon approval and an upgraded selling plan. The company charges several kinds of fees on items sold, depending on what kind of selling plan you have.

If you opt for the standard Individual selling plan, for example, you'll pay Amazon 99 cents per item sold and a referral fee. The referral fee is a percentage of the item's total sale price, including shipping costs but not taxes, and usually ranges from 8% to 20%.

Keep in mind that if you're selling media items, including books, movies, and video games, you pay a $1.80 closing fee, as well.

The upgraded Professional selling plan requires a $39.99 monthly subscription fee, but if you get it you don't have to pay 99 cents per item as you do with the Individual plan. The professional plan makes sense only if you plan to sell more than 40 items per month.

eBay lets you auction and sell a wide range of goods and has a simpler fee structure than Amazon. For most items, you pay eBay 10% of the final sale price of the item, which includes shipping costs but not taxes. If you post more than 50 items in one month, eBay starts charging you 30 cents per listing over 50.

eBay also allows you to promote your listing in various ways for extra fees. For example, you might want to set a reserve price so that your item is auctioned off for at least that minimum amount. For most product categories, the fee to set a reserve price is $5 or 7.5% of the reserve price — whichever is greater, with a maximum fee of $250. eBay charges this fee whether or not your item sells.