This is an app that doesn't allow you access unless you pay for their subscription and give them money. While the cost is ludicrous, this would not normally be an issue as there are always people willing to pay for a service such as this.
However, this is a website that is primarily used by students, including children. Their entire ad platform is designed to convince you to pay for the subscription; if you don't provide credit card information, it assumes you just don't have one, and tells you that your parents can use theirs.
As for the final result, assuming you pay for it, it's a completely terrible app with not a professional insight. As this site is used by children, with unhelpful moderators that also don't know the material, this app only serves to obstruct real learning. Garbage on a gilded pedestal, locked behind a steep paywall.
Bottom Line: No, I would not recommend this to a friend