Learn Turkish: Muhabir, sürgün pahasına kaynakların gizliliğini korudu. - The reporter protected the confidentiality of the sources at the cost of exile.

pahasına means "at the cost of" or "at the risk of". It consists of paha (price/value) + -sı (3rd person possessive) + -n- (buffer) + -a (dative case). It forms a noun compound with the preceding word. Because sürgün (exile) is treated as a general concept here, we use an indefinite noun compound, so sürgün remains in its bare form without a genitive suffix.

The lesson also teaches using the infinitive -mAk with pahasına. How would this phrase change if we used a verb instead of the noun sürgün?

To express "at the cost of being exiled", you would use the passive infinitive sürgün edilmek. The phrase would then become sürgün edilmek pahasına. Both structures are common, but using the noun directly as in the original sentence is often more concise.

gizliliğini has quite a few suffixes stacked together. Can we break them down?