You could write quality articles related to the niche of your product and submit them to article directories like
EzineArticles. Add a link to your product in the Author's bio box.
You could even set up a lens on
Squidoo about your product. Update the lens regularly and ping it on sites like
Pingoat and
Ping-o-matic. There are many other sites like Squdioo e.g.
Hub Pages,
WikiDot, etc. You could check them out too.
You could even advertise on social networking sites like
MySpace and
FaceBook.
Alternatively you could even answer questions regarding your product's niche on sites like
Yahoo! Answers and put a link to your product. Its a great source of free targeted traffic.
If you wish to give commissions to affiliates for promoting your product, you could put up your product on affiliate networks like
ClickBank (Leading Affiliate Network for Digital Products Only!),
PayDotCom or
Commission Junction. Affiliates do all the hard work promoting your product, and all you need to do is to offer them a commission on every sale in return. You could even get in touch with Super Affiliates in your niche and do a Joint Venture with them.
And there are a lot many more ways to advertise your product for free on the internet.....
Lastly, check out
Warrior Forum for some great Internet Marketing Advice
Good Luck!
/ 
