Instacart

Instacart dominates grocery delivery by aggregating inventory from 1,400+ retailers including Costco, Whole Foods, and Aldi, with same-hour delivery across most major US and Canadian cities. Its real-time comparison tool reveals per-unit prices across retailers for identical products, a feature that cuts shopping time by 25% compared to visiting multiple stores manually. Unlike #9 Rakuten, which offers no grocery-specific discounts, Instacart provides transparent pricing that has helped users save an average of $0.50 per product when choosing the cheapest retailer for each item.