There are two main ways to use a slider.
1. Use it as a product selector and give it a price.
(Woocommerce Users: also don't link it to a woocommerce product)
Please refer to the two images below for a greater understanding of how the math works behind the sliders.
In scenario #1 (screenshot below), you will notice there are two dropdowns in the same subsection. This is done on purpose to have the slider multiply the cost of renting the car by the daily rate of the vehicle and the daily rate of the insurance level. If the insurance level was a one-time price and not a daily price, then it should be added to a different subsection.
In scenario #2 (screenshot below), you will notice there are two dropdowns in the same section. But they are added in two different subsections on purpose so that the slider will only multiply the first dropdown (Gender) and not Shirt Quantity.