Ebay has taken some steps to reduce postal overcharging but these steps are easy to get round so the unscrupulous are still ripping bidders off. There are 'power sellers' whose p&p on some items is ten times actual cost! If all buyers had automatically given them bad feedback for their cheek they would not now be power sellers!
Winners can help get back at the ripoff merchants. Enquire in advance what service is being used - 'seller's standard' hides a lot of greedy sellers! Check the p&p for similar items. The seller will have done this so if they seem ignorant of a fair charge it's because they are profiting from that ignorance. Some sellers are genuinely ignorant as to mail costs - they need to quickly learn that such ignorance costs THEM money not the buyers. If you see an item you like but the p&p is far too high query it - most sellers are amenable to friendly suggestions especially if you show them the Royal Mail sites where full info' can be found. Ripoff sellers will tell you not to bid - they still hope you will.
Thinks like pottery, glass and porcelain need a lot of protective packaging: books don't! Be prepared to pay double the mail cost if good packing is necessary - up to a limit! If the seller seems to be adding a couple of quid for unnecessary packaging ask why. eBay says any costs associated with the sale should be added to the start price. There are a few unfortunate sellers who live many miles from a Post Office and their delivery cost is much higher than most so understand their problem and pay up - or don't bid!
Some sellers don't reduce total cost if more than one similar item is bought. They are allowed to do that BUT if they charge for single item mailing and then mail all purchases in one package they have defrauded you of the cost of extra packaging charged for but not used. Claim through Paypal!! You bought 'Special Delivery' and got 2nd class/Std Parcels? Then you haven't got what you paid for - 'Item Not As Described' so claim the LOT back! Many sellers choose and charge for 1st Class even when the item is far too bulky for a postie's sack. These items will be delivered as Standard Parcels so why pay for any other service? Tell the seller that he is wasting your money!!
Leave HONEST feedback: if the seller is a p&p ripoff just give bad feedback, don't pull your punches because you feel you share the blame for buying from them.