The prices given on product pages are inclusive of statutory value-added tax (VAT) and other price components.
Shipping costs are communicated to you during the basket process and reconfirmed on the order page.
The fact that the amount of VAT included in shipping costs is calculated on the basis of the goods purchased means that it may decrease if the goods purchased are subject to a lower rate of VAT. This, in turn, means that definitive shipping costs can only be calculated during the order process. As it is not permitted for them to increase they will only be adjusted to your benefit (i.e. reduced).