Hi Carrie--we just assisted a developer with a stamped concrete project.  We had a quote for the stamps made in acrylic by a local fabricator for about $600 each.  They did a sample and the developer worked with their concrete crew for a test stamp, but they just couldn't get the mix and timing right so they gave up.  The following year they ended up getting the poems fabricated in steel and just set into reserved areas in the concrete, for about the same price, with the sign company doing the labor.