To get a basic understanding of cost accounting I recommend reading the managerial accounting topics found in the second half of an introductory accounting textbook. Such a textbook is often 1,200+ pages in length since it covers both financial and managerial accounting. (A textbook containing only financial accounting topics is not helpful.) A person in the U.S. should be able to obtain a 5-year-old edition of a 1,200-page introductory accounting textbook from a reseller on Amazon.com for approximately $5.
Generally the authors of these introductory accounting textbooks will present simpler examples and explanations than those found in managerial accounting textbooks or in cost accounting textbooks. This should make it easier to gain a basic understanding of important cost accounting concepts. Armed with this understanding, you can then return to the cost accounting textbook to tackle the more complicated issues and problems.
I believe that the introductory accounting textbooks, the managerial accounting textbooks, and the cost accounting textbooks will present 15 common cost accounting topics with varying degrees of depth and complexity.