What is the difference between a price including VAT and a price excluding VAT?

A price including VAT is the price inclusive of all taxes, i.e. the price already contains the VAT component. e.g. €10 (incl. tax)

The price excluding VAT (ex VAT) is the price excluding tax (ex tax). In other words, it is the price at which the company sells its products and VAT has to be added on top (except for trade customers). e.g. €8.55 excluding VAT or ex tax.