I didn't fare well in stocks, but at least I learned a lesson.
I didn't fare well in stocks, but it taught me a valuable lesson.
ご質問ありがとうございます。
・「I didn't fare well in stocks, but at least I learned a lesson.」
「I didn't fare well in stocks, but it taught me a valuable lesson.」
（意味)株で失敗したけど、 失敗から学ぶことができた。
<例文>I didn't fare well in stocks, but at least I learned a lesson. I have to make sure I don't make the same mistake again.
<訳> 株で失敗したけど、 失敗から学ぶことができた。もう同じ失敗をしないように気をつけないと。
参考になれば幸いです。
I bought some stocks that didn't work out very well, but it was a good lesson nonetheless.
この場合、次のように言うと自然で良いかなと思います。
ーI bought some stocks that didn't work out very well, but it was a good lesson nonetheless.
「株で失敗したけど良い勉強になったと思う」
didn't work out very well「全然うまくいかなかった」＝「失敗した」と言えますね。
ご参考まで！
アメリカ合衆国 
カナダ 
