If you have any products for sale or services which you are offering to general public, then you will need to announce it to people. This will get good exposure to market your products.
There are many ways to market them. Some methods are expensive, some are less expensive and some are free. Depending on your money power to invest your can select some advertising companies to handle your publicity work. This will be little costly but will bring you good results.

Then you can go by yourself.
Showing advertisements

In TV
These are charged according to which time you select to run your advertisement, normally prime time slot will be a costly one as most people are glued to the TV in this time and it will be charged per seconds.

In Newspaper
News paper advertisement can be selected as week days and weekends.
You can select pages to post your advt Front and back are the most viewed pages and they are expensive. There are editions going international, national and particular states or cites. Depending the paper advt's colour/BW, size, placement the price may verify. Also in paper you can go for classifieds, this very cheap to post in the local news paper.

Web Advertising.
You can go for banner advertisement little high priced. You can use Google Adwords according to your financial plan.

Web Classifieds.
There are many classified web sites. Craigslist.org is the biggest one. They offer free classifieds while they charge for job posting section in USA. You can find many free classifieds in the web.

Achchi Free Classifieds - www.achchi.com