Only embed option directly from Instagram is to embed a specific post. Can not be updated automatically, would need refreshed manually.
Juicer
Possibly the best free option. The "widget" display flips, but you can set the flip timing so that it will appear to be static. Note, I was able to block their marketing logo using a style, but it added two divs which cleared the format of the page (possibly their way to stop people from doing that).
Snap Widget
Has numerous free options for slideshows and grids, but if you click on the image, it takes you to their site instead of Instagram (unless you buy a pro account). We could block that with a transparent overlay style possibly(so there would be no link).
Embed Social
Has one free option. If you want to make any customizations, you have to use their pro version, but there are a lot of customizations you can make with a pro account.