I think a quick way to make money is actually reselling products and goods online. Search online for deals on things people want, like computer monitors, mice, headphones, action figures, toys, basically anything that you might find useful. Then, list it on eBay, and try to list the price a little lower than your competitor. You will get bids in no time, and from there, you can sell them and make a profit.
Another alternative is actually buying from eBay sellers themselves. Once you grasp the price of certain niches like action figures, you may find that let's say, a batman figure is only being sold for $10. Little did the seller know, was that the figure was actually rare, and could be easily sold for 40-60 dollars. That's basically a 30-50 dollar profit right there. If you do try reselling, just make sure you write down average prices for different niches.