apple juice for baby

Holli
My baby seems to be constipated and I wanted to try giving her apple juice to her get things moving (since prune juice is pretty pricey and we won't be using much)
But, I don't know if I should have gotten the baby "mots for tots" apple juice or what? They didn't have a lot of choose from in the way of baby juices. I ended up just getting a 100% apple juice no sugar added one (that way we could drink it too).
Is that okay to give her, like watered down maybe? 
She is 6 months old.