Hi,

I personally purchase apps from Blackberry App World, and have not had any problems.  It is a very safe transaction that can be done either from a PayPal account or from a credit card.  The transactions are secure.  If, however, you have doubts, then by all means do not purchase any apps from the site. 

You might also want to check out VCast Apps from Verizon Wireless.  It features a lot of cool apps for your Blackberry device.  You can also charge items to a credit card securely or even charge it to your Verizon Wireless bill.  Check out VCast Media Store for more information at http://mediastore.verizonwireless.com/onlineContentStore/index.html#

Doc