Practicing yoga can improve your strength, flexibility, and focus. It can also remove between $5 and $20 from your wallet per class. I already have a membership to a gym that unfortunately doesn't offer yoga classes, but I occasionally like to add yoga to my workout routine. When I do, I turn to one of these online yoga videos:

YOGAmazing Video Podcast

This is the yoga resource I use the most. Run by Chaz Rough, a yoga instructor from Kentucky, the YOGAmazing Video Podcast provides yoga classes that range from 10 minutes to over a half-hour long. Each class is on a different theme, from “Yoga for Beginners” to “Yoga for Upper Body Strength” to faster-paced classes like “Morning Flow.”

Yoga Journal Practice Podcast

Yoga Journal provides 20-minute classes that can be downloaded as video or audio. The classes feature host Kathryn Budig narrating the poses while another yoga practitioner demonstrates. These videos tend to incorporate more advanced poses than YOGAmazing, and classes include “Strengthen Your Core,” “Arm Balances,” and sequences for morning and evening.

Yoga on YouTube

Searching for yoga on YouTube provides a variety of classes and instructional videos from 30-minute weight loss workouts to short seven-minute videos from Yoga Today's “Light Practice” series to “Steamy Hot Yoga,” which appears to be much less focused on the “yoga” part, and more concerned with the “steamy hot” (and I'm not talking in a Bikram heated-room way).

Netflix

Okay, this isn't technically free, but if you already have a Netflix account, multiple yoga videos are available through their instant-stream service.

A Note for First-Timers

If you are completely new to yoga, it's worthwhile to pay for a few in-person classes to learn the basic poses. Yoga can push you to move in ways you haven't before, and taking a class gives you the opportunity to have a seasoned practitioner adjust your movements so you know that you're getting the poses right. Once you understand how, for example, a downward-facing dog pose should feel, it's easier to repeat the pose in your own home. Many popular daily deal sites, such as Groupon and Living Social, frequently feature discounted yoga-class packages that would be great for getting up to speed.

If you've never done yoga before, you'll also need to purchase a yoga mat. Some of the videos do suggest having a yoga belt or block for poses as well, but if you're just starting with yoga, I'd recommend in only purchasing a mat first.

Do you use online yoga videos? Know of any good resources I missed here?