If you ever have wanted to know if it was possible to build a powerful email list using free methods then you should read this article on free list building tips.
Seven Free List Building Tips

(1) Create a blog

At the bottom of each post include a link to the email list "squeeze page" on your main website.

(2) Post Comments

This should bring up a list blogs that you can start watching. Pick 2-3 to watch and track. Now over the next 30 days, write comments (with a weblink to your website) to posts that you like or dislike.

Don't do lame stuff like, "This sucks!" or "Great job!" and expect anyone to click on your weblink. Take a minute or two to add some well thought out opinions before you write. People will click on links to learn more about people who understand and think like themselves.

(3) Forum Posts

Find a forum or discussion board of people who are within your niche market. Now lurk for a few days and learn more how the forum is run and how the admins/moderators operate. Now when you if a post that is related to your keyword or email list purpose then you can make a comment. If you have more free information on your website, you may or may not be able to make a weblink to it, depending on policy

(4) Signature Lines

If the forum forbids direct weblinks, then you should modify your forum account to include a weblink to your list squeeze page or your home page at the least. Also add a weblink your email accounts, all pointing back to your squeeze page.
(5) Write Articles
Most article directories will take how-to pieces as low as 400 words. So trot out your thinking cap and write down a 5-7 helpful tips, warning signs, "best ways to", etc. Complete with a paragraph or two per each tip, warning sign. Post in directories like EzineArticles, ISnare or Idea Marketers, etc. In your resource box include a weblink to your email squeeze page.

(6) Create Videos

It's fairly simple to create some decent looking videos using free presentation, audio recording and screen capture software. By using Open Office (Impress is PowerPoint knockoff), Cam Studio (a Free Screen Recording Software app) and Audacity (a Free Audio Editor and Recorder program) along with just a little bit of skill, you can produce a video that you can upload to You Tube. Always include your weblink in the starting and ending credits!

(7) Create Pod casts

Use Audacity (a Free Audio Editor and Recorder program) and cheap microphone (from the electronics store) to record 5-10 minute mini "talk radio shows". You can include background music or flashy sounds effects, but you must always include good information and mention at least 2 times the URL or web address of your squeeze page.
Some of these free list building techniques, granted may take some time to learn or implement but you can easily over time increase your subscriber base using these free list building tips.