Determining where you advertise online has a lot to do with your target market. If for example you are targeting youth, young adults and young professionals, then social media outlets such as facebook and Twitter are effective advertising mediums.

For other markets, perhaps look into purchasing ad space on local radio and TV station websites. Most will have packages available for purchase that include web banners, online contests which feature your product or service and some packages will also include airtime or TV time.

You can also visit local business sites and see if they too sell ad space. So long as your target market accesses the business site, then it too could serve as an affective advertising option.

Google Adwords is an easy-to-use advertising medium for online ad space. All you need is a Google account and a few minutes to compose your advertisement and you're set!