> For the complete documentation index, see [llms.txt](https://vu-custom.gitbook.io/vu-custom/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://vu-custom.gitbook.io/vu-custom/integrations-connections/upcharges.md).

# Upcharges

## **Overview**

The Upcharge system relies on a relationship between the **Base Product** (the item being customized) and a secondary **Upcharge Product** (a SKU within your e-commerce platform that represents the fee).

1. **Configuration:** Upcharge logic is handled within the VU product libraries/configuration. You define which increments or selections trigger a price increase.
2. **Visual Feedback:** When a customer selects a premium option in the VU Customizer, the displayed price of the product updates dynamically to reflect the total cost.
3. **Cart Behavior:** When the customer clicks "Add to Cart," VU actually sends **two** items to the cart:
   * The Base Product (at its standard price).
   * The Upcharge Product (representing the extra cost).

## **How Upcharges Work**

The Upcharge system functions by associating the **Base Product** with a secondary **Upcharge Product** (a separate SKU/Item).

1. **Product Setup:**
   * You must have a "Base Product" (the main item).
   * You must also create specific "Upcharge Products" (dummy SKUs) in your e-commerce platform (e.g., Shopify, BigCommerce) to represent the cost of the add-on (e.g., "+$5.00 Premium Finish").
2. **Logic Configuration:**
   * Inside the VU Admin (using JS libraries/configuration), you define which customer selections trigger the upcharge.
3. **The User Experience:**
   * As the customer interacts with the VU Customizer and selects a premium option, the **Displayed Price** updates visually in real-time to reflect the total cost (Base + Upcharge).

## **Visual Merging (Front-End Implementation)**

By default, the shopping cart will display the Base Product and the Upcharge Product as two separate line items.

If you prefer these to appear as a **single item** to the customer, this requires a visual adjustment within your e-commerce theme files. Your developer can group the items visually in the cart template so the customer perceives them as one unified product, even though they remain separate SKUs on the backend for inventory and accounting purposes.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://vu-custom.gitbook.io/vu-custom/integrations-connections/upcharges.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.