One of the hardest things about learning anything new is finding resources that are worth your time, don’t cost thousands of dollars, and don’t suck. One of the things i have not done and will not do is teach base R. I will do demos, i will explain some packages and functions along the way, but the basics of R are all free, and all range form pretty good to excellent. When you are in the early stages of learning anything, anyone that knows more than you is a resource for you. Just make sure they know wtf they are talking about, that part is harder. The next hardest part is use it everyday!
On that note, where do you start to learn R for free or cheap? I use or have used all of these resources,
In know particular order;
Books and/or PDFs
A Students Guide to R by Mosaic
The R Book
Introduction to Statistical Learning
Elements of Statistical Learning
R for Data Science
R Reference Card
R for Everyone
Interactive resources I snagged from from EdXs HarvardX R
SWIRL, Learn R in R (easy)
Try R by O’Reilly (easy)
Quick R (easy)
Online Free: