I keep a note pad in the car and bring clothespins for each shop I do. Once I finish a shop I make the notes and pin the business card or whatever to that page of notes. When I do a bunch in a day I take a cardboard box with me (I use one of those flat rate boxes from the post office) and just keep putting my finished business into it. At the end of the day I grab the box and carry it right to my computer. No more hunting through my purse or whatever for an elusive receipt, page of notes or whatever I have, it's all in the box.
Her Serene Majesty, Cettie - Goat Queen of Zoltar, Sublime Empress of Her Caprine Domain