Due to the lack of any official instagram widget, adding an Instagram feed to a Shopify website isn't quite as straightforward as one might hope. Some options for achieving this are discussed below, but to give the 2 line summary:
- For a simple instagram feed displayed on your home page, find a theme with the option built in
- For advanced Intagram integration (particularly shoppable links) try an app like Like 2 have It
Themes with a widget built in
There are quite a few themes with instagram widgets built in. They all require some kind of validation with your Instagram account (a login, Client ID or similar), but once configured work perfectly (unless your Instagram account is private - watch out for this one...). Keeping an updated list of themes here sounds too much like hard work, but the 2 developers Ive noticed doing this are Outofthesandbox and Pixelunion, so I imagine all of their themes on the Shopify theme store will have this option sooner rather than later (examples include Parallax and Grid). This is cleanest option where possible, and while not being as powerful as some of the apps, is a nice simple option.
Lightwidget appears to be the next best thing to using a theme with a Instagram widget built in. It is responsive and links to your actual instagram posts (unlike Snapwidget below). The only downsides are 1) you need to login to your Instagram site through the Lightwidget site to validate it, which not everyone may be comfortable with, and 2) the free version only updates every 24h (but only $10 for the paid version). It is also recommended by Outofthesandbox here which for me does lend some credibility to it.
Snapwidget is a third party service that lets you create free Instagram widgets that you can embed on your website - they're flexible and look fine. The catch - the links on the widget now direct you to a snapwidget page which (somewhat understandly) has a decent amount of advertising on it (this is how they make their money...). This is obviously not as nice as being directed to your instagram page.
There's lost of options here, as I mentioned the one that I would check out first is "Like 2 have it" - It seems to have very similar functionality to similar apps like Foursixty, at a much more reasonable price point. The big win here, over something simpler is the concept of Shoppable links - ie the feed shows your instagram images with links to their product pages, the theory being people get enticed by the nice instagram gallery then being able shop for the very same products in just one click.
Update: A comment below mentioned Instashow as well, which does appear to be getting good ratings.