Thanks for writing in! The WooCommerce product filter widget can be added to your sidebar by going to Appearance > Widgets. Simply find the WooCommerce product filter widget and drag it to you “Main Sidebar” area. To know more about WooCommerce widgets, please check this out:
The price filter will only display if there are enough products to filter. Having only one product is not enough. It will eventually show up of as you added more and more products with different product price range.