There are a lot of great free sources of information. This website is one of my favorites. Sign up for their daily newsletter and read it every day. Look for free webinars on SQL Server. Red Gate and Idera both have some really wonderful free webinars. Look for a SQL Saturday in your area - it's a fabulous free event, happening all over the world, bringing in SQL Server experts.
Here are a few of my favorite websites:
http://blog.sqlauthority.com/author/pinaldave/ - He's got a lot of great tips
http://www.sqlskills.com/blogs/kimberly/ - This site is well written and they cover many topics in depth - they have a lot of great people on their team.
http://www.brentozar.com/sql/ - this guy is a riot! He is funny and gives great information too!
Good luck and happy learning!