NEVER, NEVER, NEVER pay for anything on eBay via Western Union or similar. You are basically giving your money away and you will never see any goods. Use Western Union ONLY for paying someone you actually know.
Oh yes, all these kind of auctions (cheap price, email direct for 'buy now' price, bidder ID kept private etc.) are scams so avoid.
Don't even rely on feedback as most scammer user ID's are hijacked accounts and the feedback refers to the original genuine member.
Common practise to ensure you do not get scammed on eBay
Insist on a landline telephone number and call the seller to verify his ID
Get an address you can verify (
www.192.com lets you check names/adresses in UK)
Pay using credit card and Paypal ( your card covers you against fraud) if seller is abroad or into a UK bank account/cheque if in this country.
Do check feedback but make sure previous feedback history matches current auction ( e.g. if the seller previously sold tea cloths out of Texas but is now selling £10k projectors from Africa)
Be wary of auctions where the bidder's ID is kept private as nobody can contact them to either warn them or check if their auction went through ok.
Collect the item if possible and pay cash on collection
On very expensive items, consider using a company such as Escrow which acts as a middle man (you pay Escrow, they hold the funds until you receive the item then when you let them know you have got it and you are satisfied then they pay the seller). A seller who will not use this service for very expensive items should be treated with caution.
Basic stuff I know, but worth remembering as so many people have been taken for a very expensive ride via eBay!!