And for OpenStreetMap, the cost might be negligible depending on how often you want updates and how large an area you want to cover: for a small area, you can generate tiles once a year or so and just have static hosting serve them up.
According to another comment in this thread who hosts a tile server him/herself on DigitalOcean, that costs about $40. Doesn't seem terrible even for a startup, either.
Doesn't Apple's map require a developer account which costs money? I haven't used them, but I seem to remember you have to pay to develop using Apple products.
