A free program for Android, by Techdroid.

Instant Repost and Downloader for Instagram is an application that allows you to repost videos and photos from Instagram directly to your device. This is extremely easy to do and doesn’t require any special knowledge. Just open the app, select a photo or video, choose the platform you want to post to (Instagram or Facebook), and tap the button to share. You can choose which photo or video you want to share and with what tags. You can also download any photo or video directly to your device.

The best thing about this app is that it’s free. You don’t need to pay a penny to use it.