Where can I advertise a business that i have for free?

Well you can request that people put banners etc. on their sites, but generally there will be a fee that you have to pay, cause its not easy to advertise your business for free now-a-days...

i think there are some sites that provides "banner exchange" program out there, but i've never triec one of those.. it's free though 
if you want to earn money, try google adsense!

Well you could get some cards and flyers made to give to people and to post through letter boxes.

If you mean online then a quick goggle search and I found this : http://www.express-marketing.com/
. This is a banner exchange you have to display other people's banners and other people will display yours.

The best way of advertising on the net is mouth-to-mouth advertising. Get people to know you, blog about your business, and then you'll start getting visitors.

have a small signiture with a logo of your business, and get active on a lot of forums.

Dont spam about your company, just try and be helpful and a good member in the forums (depending on what the forum is about), people will click on your sig and you may get the occasional customer.

Ok