Cheapest, or least expensive
Adam,
You'got sound advice from the previous 3 posts.
My thoughts are as applicable to life in general, as they are aviation.
Cheapest per hour, may not be least expensive overall. If you find something really "cheap", but not as effective as a school that are more expensive per hour, your "cheap" route may well turn out to cost you far more money over the course of your training.
As a student with long summers I would suggest you save up to do it over one summer. Lots of flying on a very regular basis will avoid long periods due to weather etc. and will save you needing as much time re-capping. There are many threads on here about the frequency of lessons, how to approach the exams etc., so have a rummage, and good luck.
Obi Wan