"Wert marked at" is a phrase that implies a value or price assigned to an item. The antonyms for this phrase could indicate a lack of value or an unknown worth. Words such as "unmarked," "valueless," "priceless," "inestimable," "worthless," "invaluable," or "non-valuable" could be used as antonyms. In some contexts, the antonym for "wert marked at" could be a variable, where the value or price is not set and is subject to change. Ultimately, the antonyms for "wert marked at" indicate a negation of an assigned value, either because it's undefined, too high, too low, or not meaningful.