I shop on the internet quite a bit, i see two methods really
1) As with lots of bits i have purchased from marine suppliers, the web site asks for payment details, which obivoulsy get checked before the good are sent - i have never had any problems in this method
2) people selling bits, no matter if its the web, paper ..... cash in bank first then send
Title does not change until payment is cashed
What happens if you send money and recieve nothing, this gets many people. Most time now you can use paypal as an audit.
i just buy from trusted sources, integrity is everything