I had been using the services of testbook for the past 3 years. They have a good user interface and have a customer friendly apps both for test series and gk. I used the apps and services for bank exams. Their test series were the cheapest test series available in the market. We can also earn points by practising on apps and using these coin/points we could purchase the test series and practice more and perform good in exams. They also have AIM test for each upcoming bank exams. So I hope they will again come with more affordable schemes for the students in future