Desmos - Free graphing calculator, free scientific calculator
Wolfram Alpha - Free computational search engine
Symbolab - Free website that can solve math problems and show steps
Paul's Online Math Notes - An extensive collection of math notes & examples for College Algebra, Calculus I-III, and Differential Equations
Khan Academy - They don't always use the best examples in their videos, but they also have interactive self-scoring exercises.
YouTube: PatrickJMT - Some of the most well-thought-out math videos I've found! He does an excellent job of explaining topics clearly.