Gday
A mate called me about this very same scam about a week ago, he had some car item for sale for around $1500 on gumtree, the scammer claimed she (?) was working on an oil rig, and could only deal by emails as she could not make phone calls, anyway he questioned it and was sent a picture of a drivers licence with the picture of a female on it and the buyers name, said she wanted his bank details and he sent them through for her to make payment, then she got back to him saying that she had left her credit card at home and that payment would be made to him via paypal, but the delivery of $900 had to be paid to the paypal account given before paypal would release the payment to him, there was also mention of payment via some cash transfer system.
Anyway I advised him not to do anything further as it was most definitely a scam, and that he should make a report to the online scam people about it, so be wary of anybody asking you to pay anything up front if you are selling anything, I would also advise that even if you have sold someone something and they are paying by paypal or direct deposit, remove the funds from your paypal account through to your bank account and then withdraw the money from the bank account before you post the item, as these sorts of payments can be reversed by the buyer, too late once your item is in the post to them.
Luckily he uses a bank account like I do that he only adds funds to when needed and only has a small amount of cash in it to keep it open, so even if they get into your account once they have your bank details your loss is very limited.
These scammers are targeting items of lower value now as previously it was mainly high value items like cars and caravans and such, so just be aware that any buyer that seems to be making excuses or changing how they will be paying mid negotiations could be trying to get you into a vulnerable position so that they can screw you over.
cheers
stayyerAU