Q: Can I use the shopping filter feature with your themes (i.e., price filter, brand filter, etc.)?
A: This is called "Layered navigation" and is default Magento functionality.
It can be set for a category, and all product attributes which you have created to be displayed in "Layered navigation" will be displayed. The attribute “Price” is included by default. You can try it using the Magento default sample data.
"Filter by" in the category page
Navigate to Backend->Catalog->Manage Categories->Display SettingsTab
Please set anchor "YES" for catgeory.