You would place the final bid as value because it will cover the insurance by the Post Office. If the parcel got lost, that is the value they will re-emburse + shipping.
You can lie and place a higher value but if they do investigate and ask for a receipt and you print out the eBay/PayPal invoice and see a smaller amount, that's called Fraud.
Also when a buyer asks you to only place a smaller amount and make it as a gift so they will not have to pay duties, you take all the risk. If the parcel is lost you will only get what the value on the customs form, so you are out of money and product.. We have sold items that had values of hundreds of dollars and asked to place a value of $25, we refuse . We were threatened by the buyer that if he got charged duty he would give us a negative. I reported the threat to eBay. As a seller you have to cover your a$$ because in any dispute with PayPal, the Seller will always lose. Even if you place a warning that if you do not buy insurance and if the item is lost you will not give a refund and repeat the warning in the auction and invoice, the seller will always lose. The first thing PayPal asks is a tracking number, letter Mail is a stamp no tracking....you lose. Insured parcels with no tracking....you lose because there is no tracking but you are covered because you have insurance but will have to give the refund immediately and you will have to wait for example with CanadaPost 75 days from shipping to file a claim and usually wait about a month to a month and a half for the investigation and to have the refund check inhand. So in short.....AS A SELLER - COVER YOUR A$$ BECAUSE WITH EBAY/PAYPAL YOU WILL LOSE .