Lean-to shed is the simplest style, consisting of a single sloping roof is probably lowest in construction cost and easy to frame, ideal for the beginner who wants a. 4×12 lean to shed plans . sku (shed4x12-lt) emailed plans: $14.99 (8 1/2" x 11" emailed pdf. postal mailed plans: $20.99 (8 1/2" x 11" postal mailed). Step by step project about lean to shed plans free. building a small shed with a lean to roof is easy, if the right plans and instructions are used..