I bought the 100 pack from Target for around $20. It's a great value. I'm not 100% sure they're accurate for my cycles though. I tested them against Clear Blue and Easy@Home strips. Out of the 3 brands, Pregmate gave me the faintest peak lines, making it hard for me and the app to read sometimes. For a pack of 100, I don't feel bad testing more often. I'd recommend continuing to use them over a period of several months to see how your own cycle trends.