Free r Courses

Johns Hopkins's flagship 10-course Data Science Specialization on Coursera, taught entirely in R. Covers the R toolchain, statistical inference, regression, machine learning, and a capstone project. Free to audit; certificate costs money.

freeCodeCamp's 2-hour R tutorial with Barton Poulson of datalab.cc. A hands-on overview of the statistical programming language R — syntax, data types, vectors, data frames, and statistical analysis. Free on YouTube.