adding different sizes to code

Hi

I am having difficulty trying to find out how i add extra the below

I have used this code before

[wp_cart: product:price:12.99:var1[Colour|Black]:var2[Size|Small|Med|Large|XL|XXL]:end]

But now I need to create a new code for a canvas print details below
so I need to add various sizes at different prices and I can not figure it out, Any help would be much appreciated

Size Price
8″ x 8″ 19
12″ x 16″ 39
24″ x 32″ 59
24″ x 36″ 69
30″ x 40″ 79
13″ x 60″ 89

Thank you

Kathy

https://www.ads-software.com/extend/plugins/wordpress-simple-paypal-shopping-cart/