I bought them because they were on sale for half price.
「2週間前に買おうか迷って諦めた手袋が半額になってたので買いました。」は英語で「I bought the gloves I was looking at two weeks ago, because they went on sale for half price.」という表現が一番良いと思います。
2週間前に買おうか迷って諦めた手袋ーThe gloves I was thinking about/I thought about/I was looking at buying 2 weeks ago
半額になってたので買いましたーI bought (it) because it was half price./I bought them because they were on sale for half price.
I bought the gloves that I passed on two weeks ago because they were half price.
I bought the gloves that I passed on two weeks ago because they were half price.
「2週間前に諦めた手袋が半額になっていたので買いました」
・「買おうか迷った」という気持ちをより詳しく予想して付け加えるなら、I was thinking about buying them(買おうと考えていた)や、I couldn't decide whether to buy them(買うべきか決められなかった)という表現を日記に盛り込むのもおすすめです。