To stay safe while mobile shopping: Go big. Do your online business with major retailers, or those you already know, like, and trust. The chances of a major online retailer stiffing you, or of their database being compromised, are slimmer than those of an unknown.
http://robertsiciliano.com/blog/2013/05/28/how-do-i-shop-with-my-mobile-securely-2/