I'm not really sure what you mean by "valuing something as 0". I would need a sentence to really be able to fully understand what you mean and give you an accurate answer, but maybe I can guess and lead you in the right direction. I'm not sure if you're looking for a verb or an adjective or what exactly it is you're thinking of, but when something has no value (value = 0) it is said to be:
1. Worthless
2. Useless
3. Unimportant
4. Inutile
5. Free (when talking about buying something; if the dollar amount owed is $0, the item is free)
(These are only a few of the many words that could be possible)
-You could also be thinking in terms of science, but I doubt that was where you were heading, but just in case, there is also something called "absolute zero" which is the lowest possible temperature that anything (matter) can be/the absence of heat.
**However, I'm thinking that the first few words might be more of what you're looking for and are trying to get across. If you can give me some idea of what exactly you mean by a value of 0 by putting it in a sentence that would really help me to understand what it is you're looking for.