This training was modified from a presentation for Helping to End Addiction Long-term (HEAL) Health Economics training presented at Boston University on September 6, 2019. This training module introduces participants to costing techniques and considerations as the first component of an economic evaluation. We review the different types of costing methods and categories of cost, and describe important considerations when collecting costs for an economic evaluation. At the end of this module, participants should be able to describe the difference between macro-costing methods and micro-costing methods, and should be able to understand the different types of costs collected during a cost analysis. This module builds on module 1 as it describes the role of analytic perspective in determining which costs to include and the appropriate valuation of those resources.