Lu, this code will create this button.
wp_cart:Product name:price:19.99:end
You must add brackets [] for it to work. You can see my sample if you edit this page.
wp_cart:Sweet Lu Product 1:price:19.99:end
wp_cart:Sweet Lu Product 2:price:29.99:end
This code with brackets [] will show the shopping cart anywhere you put it. You must have a product in the shopping cart to see it.
show_wp_shopping_cart
Your cart is emptyVisit The Shop