The maps I have are from Mapopolis. They're fine for maps, but you can't get photos or anything like that. TomTom and other companies sell vector maps, and most, if not all, total <1GB. The format is different from raster maps, which are just graphic images. You can get vector maps of the US from the Census Bureau, and this is what the free mapping programs which provide on-the-fly routing use. They're missing some data, though, such as one-way streets, and you can easily be routed on the wrong side of an interstate highway, or the wrong way on a ramp or a one-way street. Getting all that data costs time and money, and that's why you have to pay for a robust mapping program. You're paying for the data, mostly. Mapopolis provided the actual mapping program for free, charging just for the maps. Sadly, they''re no longer in business. PDA mapping programs are quickly becoming extinct, because you can buy a standalone unit cheaper than you can get the maps alone.