Depends what youre buying .The standard rate of vat in the uk is 17.5%.
But
There is a reduced rate of 5% vat for certain goods.
1. Schedule 7A: Reduced rate
INDEX TO REDUCED RATE SUPPLIES OF GOODS AND SERVICES
Children's car seats
Domestic fuel or power
Energy-saving materials: installation
Heating equipment, security goods and gas supplies: grant-funded installation or connection
Residential conversions
Residential renovations and alterations
Women's sanitary products
This is according to government website.
http://www.direct.gov.uk/en/MoneyTaxAndBenefit s/Taxes/BeginnersGuideToTax/DG_4015895
HOPE THAT HELPED ?