3 sentences

1. 市场上的供求关系决定了价格。

   shì​chǎng shàng de gōng​qiú guān​xi jué​dìng le jià​gé.

   The relationship between supply and demand in the market determines prices.

   Source: Dong Chinese Dictionary

2. 受市场供求影响，生猪价格出现了波动。

   shòu shì​chǎng gōng​qiú yǐng​xiǎng, shēng​zhū jià​gé chū​xiàn le bō​dòng.

   Influenced by market supply and demand, the price of live pigs has fluctuated.

   Source: Dong Chinese Dictionary

3. 在市场经济中，商品的价格会随供求关系而变动。

   zài shì​chǎng jīng​jì zhōng, shāng​pǐn de jià​gé huì suí gōng​qiú guān​xi ér biàn​dòng.

   In a market economy, commodity prices fluctuate according to supply and demand.

   Source: Dong Chinese Dictionary