All you really have to do is go behind the scenes and the go to bulk edit. click on the edit prices for tote bags and enter your mark up and hit submit...then all your work will include tote bags. You can also do it individually by editing each image and positioning the image the way you want it and adding prices.
There isn't an application that I know of but there is a thread posted by Sean about them. here is the link to that discussion
http://fineartamerica.com/showmessages.php?messageid=2530527&targetid=2543523#2543523