袋 doubles as a measure word: 一袋米 (a bag of rice), 两袋面粉 (two bags of flour). Common compounds: 口袋 (kǒudài, pocket), 塑料袋 (sùliào dài, plastic bag), 袋子 (dàizi, bag).
grammar
As a measure word, 袋 directly follows the number: 一袋盐 (a bag of salt). As a noun, it needs its own measure word: 一个袋子 (a bag).
