BillGuard is a service that sifts through credit and debit card transactions to see if you're getting scammed.
The service, which calls itself "antivirus for credit cards," tells you when charges to your account look suspicious. How does it know? You -- and every other user -- train the software to find unauthorized charges and transactions that you don't really get anything out of (like companies notorious for signing you up for a subscription that you'll never use).
BillGuard is now a free service. Previously, it was a freemium model, but it looks like they can get the bills paid by contracting with banks. That means you can monitor an unlimited number of cards for free even if your bank doesn't use BillGuard.
If your credit card statement is too noisy to make sense of, this service may help you save a few bucks.
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