The field of the invention relates to methods, servers and computer program products for providing a set of prices. A computer server receives a request for a price for goods or services, such as airfares, together with parameters defining those goods or services, for example: activity type, such as airfare, hotel booking, train fare; date range; destination; origin; desired weather conditions; star ratings; keywords; any other user defined preference. One or more processors programmed with software then infer, estimate or predict estimated prices from an incomplete historical price dataset by analysing patterns in that dataset and provide the price estimates to an end-user computing device, such as a personal computer, smartphone or tablet.