I am an economics major at Princeton University. Here are the textbooks that my professors assigned for my introductory macroeconomics and microeconomics classes. The books are user-friendly and thorough with concepts. The one downside is that as they are textbooks, they're pretty expensive.

See if you can borrow them at a local library, or try buying second-hand or international versions. Those are much cheaper (the paper isn't as "glossy", which keeps the price low) and cover the exact same material. Amazon is a good place to start.

1. Principles of Microeconomics: N. Gregory Mankiw: 9780538453042: Amazon.com: Books
2. Amazon.com: Macroeconomics (9781429283434): Paul Krugman, Robin Wells: Books
3. Amazon.com: Macroeconomics: Principles and Policy (9780538453653): William J. Baumol, Alan S. Blinder: Books

If you want one book to cover everything, consider getting:

Amazon.com: Principles of Economics, 7th Edition (9781285165875): N. Gregory Mankiw: Books

I haven't used this, but I assume it's similar to Mankiw's macroeconomics and microeconomics texts.

Let me know if you have questions.