How much is insured shipping at DHL?

I sell on eBay. And if someone wants to buy something but insured shipping. Since it is a Nintendo game I would like to send it in envelope. Does anyone know how much shipping is there and if you can insure a letter at all. Or just a package?

https://www.dhl.de/de/privatkunden/preise/preise-national.html

If it fits into an envelope you can also write it by registered mail or as a value letter - https://www.dhl.de/de/privatkunden/preise/preise-national.html

https://www.deutschepost.de/de/w/wert-national.html

If I see it correctly, regular postage for the shipment + 4,30 EUR surcharge.