Distance learning is where the school send you out the study notes for you to study in your spare time, at home. They provide support, but essentially, it's up to you to get yourself through the course. The full time course uses the same notes, but you spend every day in a classroom being taught the subjects by an instructor, hence the difference between the full time and distance learning prices.
There has been much discussion on the subject of which is better, distance learning or full time, and which school is better for it. If you do a search you'll bring up many, many threads on the topic.