With PayPal & fees if an 'all in price' is agreed I would expect that to be the amount you pay
If the all in price is £10 then you would pay £10, PayPal take 3.4%, the seller pays postage
If it's £10 plus fees then make sure you pay more to clear the fees. If the seller wants a 'personal payment' don't
It would allow you to choose the option to pay fees, but is not meant for purchasing and you don't get the full protection of a quick refund in a dispute
Use an online PayPal calculator to work out fees
Avoid paying by bank transfer - there is no protection
If you realy know the person, or you are willing to take the loss if it goes wrong then you can go for a bank transfer and save 2.4%
But it's a tiny amount
If receiving money note that even when it arrives in your bank balance there are different types of 'cleared' in banking, how long it takes varies between the banks involved. It is possible for you to see the money and withdraw it but still have the payment bounce, possibly making you withdrawn and losing the item sold - make sure you are aware of the true status when using bank transfer