Virtuemart cart has a special placeholder to display Checkout messages.

These messages could be generated by the shipping of payment plugins but with the help of this plugin, you can add as many messages as you want.

Add a product to your cart and go check the cart page. You will see a message there.
You can manage the ,essages to be displayed inthe backend:

http://demo.daycounts.com/administrator/index.php?option=com_virtuemart&view=checkoutadvertise

 

checkout advertise example