Online shoppers - If you have a credit card always use your card to make purchases as it is easier to claim your funds than using a debit card.
Never pay for an item using BACS - I purchased an item for £140.00 using their details e.g. sort code, account number etc. I did not receive my item so i contacted the bank, they refused to cough up and said it was my fault as I made the payment via bank transfer. After a few more attempts they said they will send a form which I have to take to the bank and they'll reimburse me. It's called a missing payment claim.
On Ebay, if a seller says do not click on buy it now and send them an offer , DONT DO IT, unless you plan to meet them. The seller would often remove the advert so that when you pay their isn't a solid trace of your purchase. Paypal wont cover you, if they don't then you may need to claim through your card issuer.
Iphones - Never buy an iCloud locked phone even if you think you can bypass it, you will end up wasting your money.
I hope some of this has been informative and helps some of you.