I recommend getting them done somewhere that uses a digital camera (some Walmarts do) especially if you have young children. Our first attempt at getting DD's pics done when she was 7 months wasted 4 sets of film for the poor photo girl, cause she couldn't get the baby's head the correct size. We went to another store with the new digital camera for pp photos and one shot and it was perfect.
If you don't have a specific deadline for when you need the passports, then you could try doing them at home. I wouldn't recommend this route to anyone that needs them sooner than like 6 months out, because what if the photo gets rejected? You may end up having to pay those high fees to have it expedited to get it in time.