When i try to summarize stuff using this api, i get problem that subscribe first. when i click there it tell me to enter my cedit card information. And i want to consume the free version. Why should i provide this information.

I want to have some tests with my applications, and when it get well, then i can pay.

If possible you can provide documents explaing how i can use this api using php.
Thanks alot,
Best Regards.