Akismet is a WordPress anti-spam plugin, that is highly recommended. Spam comments start as soon as your blog goes live. Here is how to get the API key free.
> Click here to get started, select a personal option.
Click Get started under Basic Plan & on the next page, move the slider to the far left under column which says ‘What is Akismet worth to you’
Fill out the Akismet sign up form, and you need to make only one change. In yearly contribution, move the slider to $0, and your payment option will be done.
Finish the sign-up and click on continue. Check your Email for the key information, and add the API key into your Akismet configuration page. If you lose the Akismet API key, you can recover it here
> use this link.
Once you have added the API key in configuration page, Akismet will automatically begin protecting your blog from spam.