This is the 591st most frequent Spanish word.
robo
The act of stealing; theft.
Here, 'robó' is the third person singular past tense form of the verb 'robar', meaning 'he/she robbed' or 'robbed'.
Robó un banco ayer por la tarde.
He/she robbed a bank yesterday afternoon.
In this context, 'robo' is used metaphorically as a noun to describe an unfairly high price, equating it to a 'rip-off' or 'scam'.
Ese precio es un robo.
That price is a rip-off.
In this sentence, 'robo' is used as a noun to refer to an unlawful taking of property, specifically a 'robbery'.