To TTL or To NOT TTL

Hello,

I am getting into the one flash off camera setup for portraits.  I have been slowly purchasing items. I have a 9ft stand, softbox with speedring, and umbrella adapter.  I am now about to purchase my flash and wireless triggers (Cactus V5).  My main question is regarding the ttl option of the flash.  I am using a Panasonic DMC-FZ200.  I know that I will be using manual mode when off camera.  But I also would like to use a hot shoe flash if I need to shoot at a low light indoor event.  Is it worth the extra money for ttl support if I truely understand how to use the flash?  Been watching Zach Arias and OneLight.  I really want to lean how to use the tool the correct way and feel that ttl is kinda like auto mode.  The cheap flashes I am looking at are only really a $50 difference.  But if I go manual mode, I can get two for the price of one.  Thanks for your help.

Yongnuo YN460-II

Rokinon 980afz

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-Ryan-
FZ200