Price Slider Filter is a single click installation module for product price range filter. This will work under Filter Module (opencart default module) and you can customize the button style, slider color, mini and max value etc... from admin panel.
Installation is as simple and no files are overwritten, no complicated database queries, no trouble at all.
Please check installation doc (readme.txt).

Demo
Demo Link for Backend : demo/demo

Demo Link for Frontend

Tags - price range filter, price filter, slider filter, price slider filter, product filter, product price filter, product price range filter, price, filter