Shopping goods in the iphone. How much is it in demand?

Recently started working on a project I will not give a name in order not to advertise. Naturally a startup. The essence is as follows: this is a catalog of products for iphone with the possibility of linking a credit card and paying for goods and services.
It seems there are great prospects for an investor; online stores respond to even the most. Any comments are very interesting, the main plans to attract users who have not used such a method of purchase. If anyone has ideas and suggestions, it’s very interesting to see ...
I think we will encounter at least one huge problem that at first there will be an insufficient amount of products offered and customers will see it and don’t want to return ... The launch of the service is expected on March 15 and on April 1 it should appear in the appstore.