Some more advices to avoid online scams:

If the price is too good to be true, it is definitely suspicious

Do not insert sensitive information on unencrypted web pages

Check the domain WHOIS information to find who owns the domain

Check the website on McAfee SECURE to see if it is a certified site

RayBan, Louis Vuitton, Oakley, Gucci, etc can't cost $15 USD

Be aware of shop sites that end with .XYZ, .TOP, .CLUB, .ONLINE

Search company info and VAT number in the "about us" web page

Avoid shopping sites that use free emails like gmail or hotmail

Avoid ponzi sites that offer higher return on your investment