Splitting a purchase among multiple parties using an electronic receipt after the transaction

A computer system comprising:

• a computer programmed to:
• provide a bill for a transaction involving multiple persons;
• a receipts management module programmed to:
• receive the bill electronically on a mobile electronic device which is associated with one of the multiple persons;
• receive a selection to split the bill among the multiple persons on the mobile electronic device;
• receive a selection of an item from the bill on the mobile electronic device;
• receive a selection of a person selected from the multiple persons on the mobile electronic device;
• associate the person with the item on the mobile electronic device;
• receive an allocation of an item cost for the item and associated with the person on the mobile electronic device to thereby allocate a portion of the item cost to the person;
• split a bill total among the multiple persons according to item cost allocations;
• and
• an interface module programmed to:
• display an allocated portion of the bill total for each of the multiple persons on the mobile electronic device.