wǒ / dāng / shí / guǐ / mí / xīn / qiào / huā / le / hěn / duō / qián / mǎi / le / yī / jiàn / gēn / běn / yòng / bú / shàng / de / dōng / xi

我当时鬼迷心窍，花了很多钱买了一件根本用不上的东西。

I must have been out of my mind to spend so much money on something I did not need.