When people complain about the high cost of genealogy education, I give them a puzzled look. Some of my favorite educational resources are freely available to anyone with an Internet connection, and most of the others are fairly low-cost.
One resource I use frequently is the Board for Certification of Genealogists web site. Amongst other things, it contains a section of articles reproduced online that were published in past issues of their newsletter, OnBoard, and written by certified genealogists. Some of the articles are clearly geared toward professional researchers, but most are skill builders that anyone can use. Topics covered include using and analyzing specific records, transcribing, note taking, genealogical writing, constructing proof arguments, and source citations.
There are nearly three dozen articles online at the moment. Even researchers who have no intention of becoming certified should find something of use there.