What are some really good free internet advertising sites outside of Google Adwords and Yahoo Search Marketing

I know of google AdWords and Yahoo Search Marketing, but what are some other really good internet advertising sites that are free or very low cost to use?

Cost Per Click and Sales Conversion; Normal Range?

Hi:

I'm trying to form some reasonable expectations for internet advertising costs and results. I must be misunderstanding something because I'm having trouble understanding how people make money selling with normal tools like Adsense.

Its my impression that if you want a good placement using Adsense you need to pay {content}.65 to .00 per click. Does this sound right?

While the click-to-sales conversion will vary depening on what you are selling and what traffice you are getting, 0.5% to 2% seems to be the normal range. Is this true?

Assuming you do get a 1% conversion, and your cost per click is .00, that suggests to sell one unit of whatever you are selling you need to spend 0. Not many products have enough margin to allow you spend 0/unit on advertising, so I'm guessing some of my figures are way off.

Can anyone lease help me figure out where I'm going wrong?

Thanks