The price of the press is not what's making the crease. Low cost presses are usually cheap because they aren't built to withstand commercial application. They aren't durable.
The creases are an ongoing problem for many with the better machines as well. I rarely do dye sub, but the creases don't care what media we use.
I get creative and make pads of cardboard, folded paper towels, whatever it takes! Place them where the heat platen edge hits. Can't be too thick though.
Have covered the entire area with a folded over protective silicone sheet as well, but that takes some experimentation due to resulting changes in temp and time
