There are many variables that affect pricing.  It's important to note these are AVERAGE prices based on a 400 square foot minimum, we do smaller projects but the below prices do not apply. Things that affect pricing are...

Do we have to remove existing asphalt or concrete? How easily accessible is the area we're pouring? Will the concrete have to be pumped?  How much form work will be required, steps, porches, and sidewalks require more form work than a flat driveway.

Regular broom finished concrete is the least expensive and can range between $4-$7 per square foot, exposed aggregate (concrete with pebbles showing through) is typically $.50-$.75 more per square foot.

Stamped concrete averages $9-$14 per square foot. Factors affecting price on stamp are the color and matt selection. Reds, charcoals, blues, and greens typically cost more because the cost of materials.  Large patterns requiring a 6' matt are more because they require extra labor.