Book Flipper University Week 2 – Sourcing Lesson 1 : Intro to sourcing - Test run 8min. Lesson 2 : Sourcing Expectations 7min. Lesson 3 : Thrift store sourcing run 20min. Lesson 4: Sourcing Recap 3min. Week 1 Week 3 Caleb Roth Instructor Caleb is the founder of The Book Flipper blog, ScoutIQ, eFLIP, and is a 7-figure book seller on Amazon.