The highest interior design cost I've found is $10 per square foot. This can vary a lot depending on what you're doing with your house and where in the country you are. I've found that in New York, this is pretty cheap; however, it's expensive in California. I also find that it generally increases with the size of your house as well. A 1,000 square foot house will have a much lower cost than a 1,500 square foot house (with more square feet). So if you're building a small home, your interior design cost may be cheaper for smaller homes. If you're building a large home, your interior design cost will be higher. Astroturfs shop in karachi.