The final price of each project is different. There are too many things we, as skilled interlocking contractors, should pay attention to. For example, cost can change depending on: The design of the project The area you want to interlock The difficulty of your interlocking project Materials also play a huge role. We work only with the best interlocking stones, so the price matches and exceeds quality. However, it stays affordable, starting with a free estimate and $25 per square foot.