Where to practice for free

Is there anywhere you can go to practice online for free? I find that most play money games seem too loose to offer any real experience, even at the higher levels.

I am hoping to avoid any money play right now because I started playing a month ago, killed the play tables after two weeks, and lost about a grand on the low level money tables in two weeks...now I am halfway through Harrington's HOHE Vol 1 and am cautiously looking for some payback.