How much are they?

它们多少钱？

对金钱提问用how much。

例句：

1. I want five apples. How much are they?

我想要五个苹果。它们多少钱?。

2. How much are they altogether?

它们一共多少钱？

3. They're cute. How much are they?

他们真漂亮。他们多少钱?。