Is there any CRM for small business?

One of my friend asked me if I can build a website to manage his clients. I recommend he have a look CRM apps. So I did some search on google and tested some of them. Here is one I found very good.

https://www.zoho.com/crm/

And ZOHO has other products:  https://www.zoho.com

Which provided a free version for 10 users. with 1G space. Compare to others like insightly, this one looks cheaper and better.