[Plugin: Foobox free] Lightbox not working on site due to jquery error

I have been trying without any luck to get the Foobox free lightbox plugin to work on a website that I am currently editing: http://becomingselfmade.com

Whenever I activate the plugin extension (it is an add-on to Foo Gallery), and preview my gallery, the images open in a new tab rather than a lightbox.

In terms of the gallery settings, I’ve made sure that I’ve selected FooBox Free in the lightbox category and that the photo is set to link to a full-sized image as instructed.

Upon previewing the gallery, I can see that the class ‘lightbox-free’ has been added to the images, but when looking at the console I get the following error: Uncaught TypeError: $(…).foobox is not a function.

Does anyone have any idea how I can go about solving this? I’ve tried several other lightbox plugins and several of them ran into the same problem. Thanks so much for any help you can provide!