Confused with Pricing/ plans & Fetaures - Help !

Confused with Pricing/ plans & Fetaures - Help !

Hi,
I need to create a portal with 500 users logging in from customer portal
there will be only 1 user ((developer - me)

I have gone through the old pricing and new pricing .

The old pricing - 
https://www.zoho.com/creator/help/zoho-creator-old-pricing.html
Professional Express allows Unlimited Users BUT
does not allow cistomer portal as an addon - is this correct?

The New pricing -
https://www.zoho.com/creator/pricing.html
is even more confusing cause its limited users.

If someone signs up through the customer portal - are they considered users? 
thanks