No, NSX manager is not free. Yes, you have to deploy controllers.
There is a 'free' version of NSX, but it's only intended to be used with 3rd party anti-virus products that utilize the NSX guest introspection features. In theory, you could install this version of the product, but all of the other features will be locked out except for guest introspection. In that case, you wouldn't be able to deploy controllers, edges, or use any of the routing/security functionality of NSX.
Hope this helps.
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