Supermarket price dataset on gluten-containing and gluten-free foods

The dataset is obtained by surveying the on-line shop of four major supermarkets in the UK in August 2014. The sample of supermarkets is composed by the top-three and one major upscale chain, which jointly controlled 68% of UK market shares in 2014. All of them had a dedicated web-page for on-line shopping with an explicit indication for gluten-free products.
Data were collected on a survey window of 30 days in August 2014.
The search focused on all the products in the "Bread and Cereals" COICOP category, which includes the following five groups: bread, flour, cakes buns and pastries, biscuits and crispbread, other cereals and cereal products and their subgroups.
Prices (in pence per 100 grams) of all gluten-containing cereal products in each group were collected.
Similarly, prices (in pence per 100 grams) of all gluten-free cereal products in each group were collected. Only those products certified as suitable for coeliac consumers were classified as gluten-free.