Costs

Because the work is labor and material intensive, expect to pay from $2.50 to $5 per square foot for a four-inch thick, broom sweep-finish concrete patio. For stamping, plan to spend around $6 per square foot in most regions. An 80-pound bag of concrete mix costs about $5 and yields about .6 cubic feet.

Exposed aggregate can start at around $4 per square foot in many areas of the country. Concrete countertops are generally considered for the high-end user and are priced similarly to granite. For a 1.5"-thick custom countertop expect to pay $70 to $140 per square foot plus $50 per hour for installation. Be sure to add shipping costs to your estimate.

Concrete projects are generally quoted on a linear or square-foot basis. Of course, pricing depends on the geographic location, thickness of the concrete, availability of resources and number of professional concrete finishers in the area. Obtain at least three quotes for any project to ensure that your project is fairly priced. By hiring a professional concrete finisher, owners add a unique and value-added element to their property.

Source: http://www.networx.com/article/pricing-concrete-and-concrete-finishing