What is the minimum threshold of wealth that disqualifies a person from fasting for the expiation of an oath?

Primary text

The condition for fasting rests upon the absence of sufficient means, as established by the verse: Whoever does not find [the means], then three days of fasting (Quran 5:89). One who finds wealth exceeding their own sustenance and the sustenance of their dependents for the day and night is considered to 'find' and is therefore obligated to perform the expiation with wealth based on the apparent meaning of the verse. Since this obligation is a right that does not increase with the increase of wealth, the standard applied is the amount exceeding the sustenance for the day and night, similar to the ruling for Zakat al-Fitr.