There are many ways to get tricked online but the most popular way is the good old Ebay Scam
Lets say I buy a Copy of Windows 10 for $249.99 i get the USB it ships to my Mansion but there is nothing on it the USB is blank.
WARNING!!!! BEFORE CONTACTING EBAY TRY REACHING OUT TO THE SELLER VIA EMAIL ITS ALWAYS BETTER TO TALK ONLINE WITH A SCREEN NAME THEN WITH YOUR REAL NAME. NEVER MEET THE PERON IN REAL LIFE YOU COULD GET FURTHER SCAMMED OR THE SELLER COULD HARM YOU WARNING!!!!
Remember you have to Scam the Scammer into giving your money back. If he dose not cooperate message papal Ebay or your credit card company. Thanks and happy shopping