Hi, guys!
App ratings have huge impact on app ranking and app installs. More 4/5-star ratings can drive you get increasing revenues in a short time. Thus, as an app developer, you should not ignore the importance of app ratings. Especially in the iOS 11, the Apple have pay more attention to app ratings.
To get app ratings, I recommend to get app ratings from BuyAppRatings. It majors in offering app ratings for free apps, and you can choose any countries that you want to target. In addition, their price is very low, each rating is priced at $0.5. Also, they provide the coupon for you if you place an big order.
Hoping my post can help you a lot!