Top Ways to Promote a Business Online for Free

1. People's Guide
One of the newest sites, but notable for being the cleanest and simplest way to add a free business listing. As these 100+ cities have just gone live, our advice is to get in early to pick up the most traffic.
2. Google Local
Any land-based business should be on Google Local.
Tightly integrating with Google Maps, Google Local is a great way to get your business to show up on Google searches.
3. HotFrog
Another strong & multi-national business-listing site.
HotFrog is a nice simple business listing site (no reviews), active in several countries round the world, including the UK and Australia.
4. Windows Live
The Windows Live Local Listing Center is also free with reasonable reach.
Launched in October 2007, Microsoft's Windows Live Local Listing Center service allows business owners to add their business information within Live search and Virtual Earth.
5. Yahoo! Local
Like the People's Guide, Yahoo Local is a combined business listing and community review site, organised by location and category.
Pretty clean and well laid-out site that's certainly worth adding your bricks & mortar business to, if your city is featured. Wide range of categories too.
6. Yellow Pages.com
Needs no introduction for most people. Strong brand recognition.
Yellow Pages is certainly big in the US and UK. The big US site does offer a free listing.
7. Best of the Web.com
Offers free advertising for the first 60 days only.
Basically premium search results ad placement, similar to AdWords, the free 60-day trial is worth taking advantage of.
8. Adland Pro
AdlandPro has apparently been offering free and paid advertising services to small businesses since 1996. Allows you to place free ads in classifieds and community pages, and also in a "Free Traffic Exchange" system, which looks a little riskier.
9. Squidoo
A good number of lenses on the Squidoo network offer the opportunity to add a link to your site, free.
Squidoo gives you simple tools to build your own web pages, and get a share of ad revenue, so it's also a route to a budget web site where you can promote your products or services.
10. eBay
OK, maybe not free, but don't overlook finding advertising bargains on eBay
Don't forget that a lot of people auction promotions on eBay. It's possible to pick up really cheap mailouts or ad runs, without investing too much time either.