Floor-plans are one of the easiest and highest profit margin add ons that you can offer. Cubicasa is FREE to use for the most basic floor-plan that they offer. There are options to add fixed furniture on to the plan, which is what we do, and a couple other colored options to easier showcase bedrooms, bathrooms, and shared spaces. They also have an option for a "rush order" which we do every time to make sure we can deliver it next morning.