Magento 2: Show price for out of stock configurable products

 If want to show price for out of stock configurable product price you need to check 

vendor/magento/module-configurable-product/Pricing/Price/ConfigurablePriceResolver.php

Find function on line number 61

public function resolvePrice(\Magento\Framework\Pricing\SaleableInterface $product)

Before Editing :::

public function resolvePrice(\Magento\Framework\Pricing\SaleableInterface $product)

    {

       $price = null;

       foreach ($this->lowestPriceOptionsProvider->getProducts($product) as $subProduct) {

            $productPrice = $this->priceResolver->resolvePrice($subProduct);

            $price = isset($price) ? min($price, $productPrice) : $productPrice;

        }

       return (float)$price;

}

After Editing :::

public function resolvePrice(\Magento\Framework\Pricing\SaleableInterface $product)

    {

        $price = null;      

        $assPrice=array();

        foreach ($this->configurable->getUsedProducts($product) as $subProduct) {

            $productPrice = $this->priceResolver->resolvePrice($subProduct);

            $assPrice[]=$productPrice;

            $price = $price ? min($price, $productPrice) : $productPrice;

        }

        if (!$price) {

            throw new \Magento\Framework\Exception\LocalizedException(

                __('Configurable product "%1" do not have sub-products', $product->getName())

            );

        }

        return (float)(min($assPrice));

    }