I’m working on something like this right now. And the first issue is the need to filter the output of the _regular_price that vendors see on the product-edit form. In order to do that, there needs to be a filter for $field in the class-wcvendors-pro-form-helper.php file. I added one myself at line 110:

} else { 
 	$field = apply_filters( 'wcv_product_input_field_modifier', $field );

		if ( $field['show_label'] )

Then, in my functions file, if I want to change the price that vendors see while editing:

function change_price_before_display ( $field ) {
	if ( $field['id'] == '_regular_price'  ) {
		$field['value'] -= /*My markup value*/;
	}
	return $field; 
}
add_filter( 'wcv_product_input_field_modifier', 'change_price_before_display' );

Now, I’m moving on to other pieces of this project. But I am wondering if, @digitalchild , you could add an input field filter like mine to the next release? Thanks.

Thank you, Jamie. I’m glad there was already a filter in place. I’m sorry I failed to notice it. This works:

add_filter( 'wcv_product_price', 'add_product_fee' );
add_filter( 'wcv_product_sale_price', 'add_product_fee' );
function add_product_fee( $field ){ 
	$value = get_post_meta( $field['post_id'], $field['id'], true );
	$field[ 'value' ] = empty( $value ) ? '' : $value - 450 ;
	return $field; 
}

Of course, I am aware that I need to save the values in the db with the markup applied, and I finished that up yesterday using this:

add_action( 'after_setup_theme', 'markup_puppy_price' );
function markup_puppy_price( $post ) {
	if ( isset( $_POST[ '_regular_price' ] ) ) {
		$_POST[ '_regular_price' ] += 450;
	}
	if ( isset( $_POST[ '_sale_price' ] ) && $_POST[ '_sale_price' ] !== '' ) {
		$_POST[ '_sale_price' ] += 450;
	}
}

Just to explain, we want all prices to be inclusive (no additional fees or shipping, and the buyers don’t see our fee), and we will be arranging shipping, which is why the 450 is so important. So, the 450 will be coming to us, but we don’t want our sellers to be responsible for adding our fee when they’re entering their prices. This way, the seller only needs to think about their sale price and not worry about any math or remembering to to factor in our shipping markup, etc. The seller always sees “their price” and the db always has the total price.

Again, thanks for your help.