Stand alone .PDF scanners - I use Adobe Scan and am also trying Stack by Google (Area 120 app). What's nice about these two apps is that they convert your receipts to .pdf files with OCR (optical character recognition) so if you needed to search for a receipt you can. I don't have a perfect system, but I can find any receipt.
You can also send files by attaching docs to emails, etc. Not sure if you can do that with the other softwares.
Mileage Tracker: I personally use TripLog. Never failed me and very easy to get records and summaries. It's not free, but it's not costly either. For TripLog, I have their TripLog Beacon, which is a USB device you plug into each car. When you start the car and drive, it automatically knows which car you are driving and records that trip for you. You can easily designate locations as Business or manually assign your trip as Business or Personal, etc.
