It's a good sheet add-on - tracks both Android & iOS apps. Currently, we are offering 50 keywords a day for users who signup using gmail (which can be increased to 200 upon request), and 200 keywords a day (upto 5 users per company - i.e. track 1,000 keywords a day per company) for those who have signed up using a corporate account.

If you'd like to refresh the ranks every n hours, it can handle that.