What do you want to buy?

你想买什么？

What do you want to buy in the mall today?

你今天想在商场买什么？

When you want to buy something expensive, what do you do?

当你想买昂贵的东西时，你会怎么做？

Like what? what do you want to buy

比如什么？你想买什么

What do you want to buy first?

你想先买点什么？

MOM; I will go shopping. Oh, what do you want to buy?

我要去市肆。哦，你要买些啥子?。