In reply to running123:
There are loads of scams on Facebook. Transfers and PayPal as friends and family being the usual culprits.
Provided you inspect the item to make sure it works and are in the same building as the item before sending money then these scams fall over (unless they are violent thieves but that's extremely unlikely).
What they could do is claim they haven't received the money yet and ask you to come back tomorrow. If this happens you are being scammed. But you know their address at this point so it's risky.
Don't agree to meet in a public place and transfer the money there. You have no come back this way and it's a red flag.
I prefer Paypal as a purchase transaction but a thief would never agree to this as Paypal hold the money to give you time to complain.
Post edited at 13:14