I'm developing a webshop that provides free shipping when the cart total is above a certain amount, let's say $100. In case a customer has a cart with $30 subtotal, she/he has to add items in value of $70 for free shipping.
So I want to display the following information as succinct as possible: Add more items to your cart in value of $70 for free shipping.
Being a non-native speaker I'm uncertain about this part: "items in value of ...".
Is that correct? (Any other improvements are welcome)