caustic soda

I use caustic soda to clean my equipment, would i still need to sterilize or would all bugs be killed off with the soda? 

Assuming you mean sodium hydroxide, it depends on the concentration and contact time.  A strong solution will dissolve just about anything organic.  You would have to rinse it extremely well.  I'd stick to the usual cleaners and santizers.  The cost is minor compared to what you have invested in a batch of beer in terms of time and material.

You need to wash caustics off with your normal detergent then sanitize as normal.

I would still mist it with some StarSan after a good rinse.