I've always liked the looks of something like this.
We have horse fencing at our property so does nothing to contain the dogs so I've been wanting to have something like this added for the pups to go out off leash protected.
They can play off leash if we are playing ball or doing something but for quick potty breaks at night etc, a little fenced in area would nice.
So I saved this photo - maybe it'll give you an idea!
It's just white picket fencing. Not sure how costly it is.