For years, Chase and Citi credit cards offered a generous, under-the-radar benefit that protected cu

For years, credit cards from JPMorgan Chase, Citigroup, and others have offered price protection, a benefit that refunds customers up to $500 if they buy an item and subsequently spot it cheaper somewhere else. Filing a claim was a laborious task, so few people ever did. Apps like Earny have emerged that use bots to automate the price-protection process, connecting with users' email accounts to monitor purchases and hunt down refunds. Insiders say the rise of these tools and services has...