CoSplit
Splits a grocery receipt item by item, so everyone pays for what they actually took home.
Every week a few of us drive to Costco and come back with one carload. Corn comes by the dozen, a cake feeds six, and the vegetables come in bags nobody finishes alone — so most of it gets shared, and not always by the same people.
Not all of us have a membership, so one person pays for the whole cart and the rest pay them back. That is the hard part: one long receipt, with tax and discounts on it, and every line shared by a different group.
CoSplit reads the receipt for you. You fix anything it got wrong, mark who had what, and it works out what each person owes. Getting the last cent to add up took a few tries. It started as a weekend project at uOttaHack 8, a student hackathon in Ottawa, and I rewrote it on my own afterwards into something we could rely on.
We still use it every week, and that is where the changes come from: a real receipt turns up a problem, so I fix it. That is most of what is in the changelog. It is open to anyone, and other people turned out to have the same problem.