Others charge a relatively cheap session fee but it does not include any photos and those purchases can add up quite significantly and can come as quite a surprise. With my packages, the costs are disclosed upfront with no surprises.
The second part of the equation is around editing. In general, photographers who offer very cheap deals, shoot their photos in JPEG and you get 10 photos straight out of the camera, good or bad. Photographers who charge more, generally shoot in Raw. Without getting too technical, a JPEG has been 'processed' by the camera, where as a Raw image contains all of the information from the photo and is processed on the computer by the photographer. It loses a lot less detail and can be perfected with the human eye while maintaining it's high quality. In general, I spend between 3 and 6 hours editing the photos after my sessions to get them just right.
The moral of the story is that there is a place for all kinds of photography to meet every budget.