the best places for free/cheap content. ?

I am alway's in need of content, right now working on an car rental site but need small reviews on certain cars, things to look for when renting a car etc..

I know there are programs out there where people wil write certain amount of text content inexchange for a link .. like this http://www.ideamarketers.com/

Does anyone have any links they can share ? maybe we can get a nice list of various content providers going for everyone here at DF ..


1.http://www.ideamarketers.com/
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