Alternatives to the Daysy

E • Animal lover, artist, & wannabe chef. 18/CA 🦋💗🐺✨♏️
Hi ladies, 
If you haven't heard of it, the Daysy is a fertility tracking device which works by taking your basal body temperature right when you wake up every morning. Apparently, it's 99.3% accurate. I have been learning more about fertility and <a href="https://play.google.com/store/apps/details?id=com.glow.android">tracking ovulation</a> and am seriously considering getting the Daysy. My only issue is that it's $330, which is a lot of money for a little thermometer!
Have any of you used it? Results, thoughts, opinions?
Do any of you have recommendations for alternatives?
Thanks so much! 💗