Promo codes can be applied on the checkout screen when placing an order. There are a couple types of promo codes, ones that automatically apply to your order, and ones you have to manually enter on the checkout screen.
Promo codes that apply automatically
Two types of promos are applied to your cart automatically, so they do not need to be manually entered:
Free delivery promos
You will automatically receive free delivery if your subtotal after any promos are applied exceeds the amount required for free delivery (currently $40 in most areas).
New user promos
If you are a new user and use a promo code that is valid for multiple orders (for example, $20 off your first 2 orders), then the promotion will automatically apply to all orders after your first order.
For the first order, you may need to manually apply the promo code to your cart.
Promo codes that must be manually applied
With the exception of free delivery promos and discounts for new user promos that are valid for multiple orders, all other promo codes must be applied manually at checkout.
Manually apply a promo code by following these steps: