Here are some articles that will help educate you more on the concrete industry:

Stamped concrete versus other paving materials
http://www.concretenetwork.com/stamped-concrete/comparison.html

Five Friendly budget ideas
http://www.concretenetwork.com/stamped-concrete/budget-design-ideas.html

Stamped Concrete Cost
http://www.concretenetwork.com/stamped-concrete/cost.html

How to estimate concrete?
http://www.concretenetwork.com/concrete/howmuch/calculator.htm