Athenodorus legit titulum auditoque pretio, quia suspecta vilitas: What was Athenodorus suspicious about?

Subject: Latin/GCSE

Q: Athenodorus legit titulum auditoque pretio, quia suspecta vilitas: What was Athenodorus suspicious about?

A:

Athenodorus was suspicious of the cheapness (vilitas). The word 'vilitas' is a nominative feminine singular noun and so agrees with the adjective suspecta which means 'suspects/suspicious'. Therefore, the clause is literally translated as 'because the cheapness was surprising'. The verb to be must be supplied here. 

The sentence as a whole:

'Athenodorus read the label and afterwards paid attention to the price, because the cheapness was suspicious.'

The 'quia', meaning because, signals that a  causal clause will follow.