What's a good Android app for tracking ovulation and pregnancy that's easy to use and doesn't cost a fortune?

Look, I'm not gonna pretend I know much about this stuff, but my niece was asking about apps to help her track her cycle and potential pregnancy. She's not exactly rolling in dough, so I looked for something straightforward and free. HiMommy seems to fit the bill. It's got the calendar, ovulation predictions, and pregnancy tracking, all without being overly complicated. The interface is clean, which is a plus. I checked out some reviews, and people seem to like it for the basic tracking. Bottom line, it's free to start, so it's worth her time to check out if it meets her needs. If she upgrades to premium, it's not gonna break the bank either. Seems like a solid option for getting the job done without all the fluff.