Just out of interest , how much did it cost?

我只是好奇问问，这个花了你多少钱？

《牛津词典》

I attended the lecture out of interest.

我听讲座是出于兴趣。

youdao

We have been following the debates not out of interest but because they are like family.

我们关注他们辩论的原因并非出于一时兴起，而是由于我们像一家人。

youdao

Paying out lots of cash, unless you really have to, is not in the interest of the firm and is not in the interest of the public."

VOA: standard.2010.07.23

Unfortunately, I've never taken a course in it, but I've started reading it lately out of just my broad intellectual interest.

遗憾的是,我从未上过有机化学课,但我最近开始读一些相关的书,这是我广泛爱好中的一种

耶鲁公开课 - 金融市场课程节选

Why don't I lend some of it out and I can earn interest on the loan and make money.

为什么我不贷一部分出去呢,这样我就可以通过贷款赚利息了

耶鲁公开课 - 金融市场课程节选

Out of interest the spread traded at 179 basis points as recently as six months ago.

FORBES: Stock Rebound Trips Up Bonds

And how many people get them out of interest, to be a part of a crazy fad, like Fifty Shades of Grey, for instance.

FORBES: Not The Booker's Sam Jordison Considers Self-Publishing Award

"We came with all the family, we do it out of interest, really, this is such a memento of that event, " says Elena Belizkaya of the hoard.

BBC: Chelyabinsk gripped by 'meteor fever'