In my experience, you need to check and compare the prices of companies selling studios in backyard before you buy. I paid over $20,000 for my studio to be installed. Aaronbackyard Creations charged me $1,200 for Concrete, I think it is too expensive as they hired a man to dig holes (my studio only needed to dig 4 holes to put the concrete for studio to stand but for your studios may need around 12 holes) on the ground (deep 20cm/ hole) and put the concrete in the holes. One worker worked in 1 hour. The 20kg concrete bag is sold $12/ bag in Bunnings warehouse. Also flyscreen door (size about 1.8m x 0.8m) ( the net door to prevent insects like mosquitoes, flies...) is $500, too expensive. They install a studio in 2 days (a builder and an assistant worker), they charged nearly $4,000.