Photograph: Andrew Matthews/PAThe drumbeat of Black Friday is unrelenting as the global retail sector looks to fill its boots at the expense of consumers. Cantillon’s inbox is overflowing with surveys and studies, all designed to persuade us that this coming weekend is a wonderful opportunity. Amazon, who else, has helpfully published a report, arguing that online shopping is helping to keep prices lower for Irish households. Specifically, for every 1 per cent increase in online shopping activity, annual inflation decreases by approximately 0.03-0.06 per cent. The bottom line: Amazon says that, without online commerce, prices would be about 4.1 per cent higher today than they are.