How many sheets / workbooks can I create?

I am new to using ZOHO and would like to use it extensively for my blog for various purposes. Now I need to know:

How many workbooks can I create in a free account? (I have no plans to buy any paid stuff right now)
What are the limitations (other than number of workbooks, if any) in free account as compared to premium/paid version?

Thanks in advance for assistance

Mohit