我们有仅售25元的毛衣.

We have sweaters that will cost you only 25 Yuan each.
注意一定要用each避免歧义.

而至于用sell的话,怎么翻都觉得有点蹩脚.
We have sweaters sold at the price of only ￥25.
这个相对通顺.

这个问题刚有人发过.答案很全,最佳答案也不错.

We have the sweaters that sell 25 Yuan only

We are selling some sweaters at just 25 Yuan

We have sweaters at the price of only ￥25.