Later used to be called Latergramme which we have covered in the past. They moved to a paid model about 18 months ago, but recently created a free level which allows Instagram users basic analytics to their account.
Once you sign up with your Instagram account, you’ll be taken to a screen where you can schedule posts for future posting. The basic statistics available will tell you how many likes and comments your pictures got in the last 30 days, and what post performed best.
You can also repost other peoples posts from the dashboard – you can search for content and add it to your own library, and then repost later. The way that Later deals with reposting items and scheduling is that it will send a notification to your phone and will copy the caption for you to paste into Instagram. They’re currently working on being able to schedule posts with multiple images, so keep an eye out!