Shortcode for increasing quantity before adding to cart?

Hi, is there a shortcode to add more than 1 quantity of an item before adding the item to the cart? For example, I am selling consulting services with a minimum of 3 hours at $45 per hour. When the user adds the item to their cart, it should add up to $135 with the quantity at 3. How do I do this?

Thank you.

http://ww.wp.xz.cn/extend/plugins/wordpress-simple-paypal-shopping-cart/