I am trying to apply a discount to a carts total price, but I can only do it to the item base price and not the over all price. I Googled and came across this post in the w
As of late 2018, the best way is to use get_cart_contents_total(). This is the total of items in the cart after discounts.
get_cart_contents_total()
WC()->cart->get_cart_contents_total(); // Float
Other methods are available for more specific needs, just have a look at the docs.