What does quantity mean at checkout?

This means that you are able to have multiple of the exact same subscription type.

For example

At Home Subscription 2 x 250g [500g]

Frequency: Weekly

QTY: x 1

You will only be receiving 2 x 250g [500g] weekly.

If you were to x 2 QTY, you will be receiving 4 x 250g [1kg] weekly.