Debt is singular, so the correct form of the verb to appear is appears. Also, debt is spelled D-E-B-T, no P. "Dept" is usually an abbreviation for "department".
With the correction to verb conjugation and the spelling of "debt", your first example is fine.
The second one is wrong (apart from spelling "debt" correctly). "Appears" can be used as a linking verb, that is where its object is an adjective, and in that case can be followed by to be or not - "you appear tired" or "you appear to be tired". However, when "appears to be" is followed by a noun, the to be needs to be there. "Your debt appears large" would be fine, but not "your debt appears $500".
The final one is fine, apart from the spelling of "debt".