Point of sale system, inventory system, and methods thereof

1. A method for conducting a purchase transaction using a wireless communication device, the method comprising:

receiving from a mobile application module executing on a wireless communication device instructions to initiate a purchase transaction by a server application;

verifying and authorizing the mobile application module by the server application;

receiving from the mobile application module identification information about an item to be purchased to the server application;

retrieving via the server application at least one of price and product information based on the identification information;

completing the purchase transaction by automatically electronically debiting a user account,

wherein the mobile communication device is configured to wirelessly communicate with a weight scale to weigh variable weight items, and

the weight scale is configured to wirelessly transmit a price based on a weight of a variable weight item to the mobile communication device and at least one of the server and a barcode label printer.

2. The method of claim 1 , further comprising transmitting the at least one of product information and price from the point-of-sale server to the wireless communication device.

3. The method of claim 1 , wherein the item identification information is obtained by scanning a product code.

4. The method of claim 1 , wherein the item identification information is obtained by photographing the item.