eBay is one of the best money making opportunities on the internet. It is easy to make money on eBay.
I got started on eBay when it was pretty new. At first I was just buying stuff, but was soon selling stuff as well. My main interests at the time were books. I was buying and selling collectible modern fiction books.
There are people who actually who run businesses that do nothing but buy and sell on eBay.
To start selling on ebay, you will need an account. They are free. Simply sign up. You will probably wanted to get started more as a buyer than a seller to get used to how eBay works.
Once you are used to how eBay works, you need to figure out what you want to sell. The best place to start is with something you know. Do you collect books, fishing equipment, cameras, watches? Look at your own hobbies. You probably know what various stuff is worth. Look on eBay and see what people are paying for things.
You need to know something about what ever you are selling. If you try to sell books, but can’t tell a first edition from a book club edition, you will not do well.
Once you get a feel for what stuff is selling, and for how much, you need to find a source of supply. Maybe you can find the stuff at garage sales, thrift stores, antique stores, etc. If you find an item for $10, that you can sell for $100, great! Go for it! If you find an item that you can buy for $100, and sell for $1000, that’s a $900 profit (minus ebay commissions, etc)! Heck, you can even find deals on eBay. More than once I have bought something on eBay, and turned around and sold it for more.
So try to find a niche. Stuff that you know something about, that you can find a decent supply of for a low enough prices, that is selling enough on eBay, and for prices that allow you to make a proifit.
Another potential source of supply are drop-shippers. Lets say you sell a widget on eBay for $20. But you have a supplier that will sell you widgets for $15. You simply have the supplier ship the widget directly to the buyer. And you make a $5 profit. Sell 100 widgets, and that is $500.
Do whatever you can to keep your customers happy. You want the best feedback rating you can get. Ther better your feedback rating, the more likely people will be to buy from you. People may pay a little more to buy from someone with a great feedback rating than from someone with some negatives. If occasionally you have to refund money, do it. It is just a cost of doing business. If you stiff a customer of $5, you win in the short run, but it might cost you more than $5 in the long run when they leave a negative feedback!