To enable this, create a smart collection named All Products and set the condition to 'Product price is greater than 0'. You can create a collection through the 'Collections' menu in Shopify admin. Or you can turn this section off through theme settings.
Grab yourself a HUGE 1KG bag of Pick N Mix.
You can customise your own selection by simply clicking on up to 10 images, which will then be added to your bag.