i going to start a job in the next 2 days laying tile over a outdoor patio. i went and looked at it today its about a 500sqft job, i was wondering if anyone had any suggestions on what type of materials ishould use. now there is a slope on the entire area, and there are no cracks in it, the ditra would cost around 6 or 7 hundred dollars alone. this persone doesnt want to spend that much money on it. are there any cheaper options.