[Android] $0: Hydro Coach PRO-Drink Water (Was $7.99), Grocery List App: Bigbag Pro (Was $2.89), SOMEDAY, Shan Gui @ Google Play

Excellent rating 4.6 from 8,393 users. No Ads but got IAP
I think, this is must have app now a days.

Hydro Coach is the most motivating water drink reminder and water tracker app of 2018 💪💦

Drinking water regularly is a big challenge in day-to-day life. Hands up – who really drinks enough water every day? Hydro Coach will help you by calculating how much water you need, tracking what you drink, and gently reminding you when to drink. It's time to unleash the power of water to improve your health. Because your health is worth it!

PRO features:
⭐️ Unlimited Diary. Look back to all past days in your diary.
⭐️ Additional monthly statistics and unlimited weekly statistics.
⭐️ More widgets (e.g. 1x1 widget for fast drink inputs).
⭐️ Use hydration factors to define how well drinks are hydrating or dehydrating.
⭐️ Fast and easy intake from each notification.
⭐️ Export your drink history intor a CSV file.
⭐️ No ads.

Benefits of drinking water for your health:
💧 It’s an effective method of combating stress and tiredness
💧 Drinking enough water can clear up your skin
💧 Drinking enough water can improve your health in a few days
💧 It’s beneficial to weight loss and the basis of every professional diet
💧 Drinking more water can relieve headaches

Key features:
✅ Improve your health with personal drink notifications
✅ Keep perfect track of your water balance through a simply designed diary
✅ Get a graphical insight into your water drinking habits with week and month statistics
✅ Practical widgets provide clear information about your water intake
✅ Create custom drink volumes easily
✅ Supports imperial (fl. oz.) and Metric (ml) units
✅ Share your water intake with your friends
✅ Direct water input through your android wear
✅ Synchronization with your google account
✅ Fitbit, Samsung Health and Google Fit

How it works:
Our formula calculates your ideal personal water requirement based on multiple factors like age, weight, gender and lifestyle. Select your favorite glass you normally use, and Hydro Coach will remind you to drink and refill it.

and Few more highly rated apps with no Ads, No IAP.

• Grocery list app: BigBag Pro
• SOMEDAY
• Shan Gui