sniziti

1. (of prices, costs) to lower; to cut; to reduce
   Prodavnica je snizila cene za trideset posto. — The store cut its prices by thirty percent.
   Banka je konačno snizila kamatu. — The bank finally lowered its interest rate.
2. (of voice, tone) to lower
   Snizi glas, deca spavaju. — Lower your voice, the kids are asleep.
3. (of temperature, level) to lower; to bring down
   Ovaj lek će ti sniziti temperaturu. — This medicine will bring your temperature down.

The participle snižen is common in shops: sniženo means "on sale". In sniziti glas/ton the verb is transitive.