I get sharing buttons all over the homepage — in the homepage's Sliders and under the listed Portfolio elements, but I just want one set of them below the page elements and above the footer so that visitors can easily share the homepage.
Jetpack Sharing buttons allow you to share Posts and Pages, but not links to your home page. In this case, you're probably better off adding the buttons without any plugins. It will allow you to hardcode the URL values to use the home page URL. You can use the following button generators to generate sharing buttons:
https://developers.facebook.com/docs/reference/plugins/like/
https://twitter.com/about/resources/buttons
I hope this helps.