Wordpress - WooCommerce: How to edit the get_price_html

Core and plugin files should never be edited directly, as any updates could overwrite your changes. If you look in WooCommerce source at the get_price_html method, there are a number of filters available to modify the output of the function.

See add_filter in Codex for more info on adding filters to apply_filters calls.

From get_price_html in class-wc-product:

return apply_filters('woocommerce_get_price_html', $price, $this);

So to add your own filter:

add_filter( 'woocommerce_get_price_html', 'wpa83367_price_html', 100, 2 );
function wpa83367_price_html( $price, $product ){
    return 'Was:' . str_replace( '<ins>', ' Now:<ins>', $price );
}

function wpa83368_price_html( $price,$product ){
   // return $product->price;
    if ( $product->price > 0 ) {
      if ( $product->price && isset( $product->regular_price ) ) {
        $from = $product->regular_price;
        $to = $product->price;
        return '<div class="old-colt"><del>'. ( ( is_numeric( $from ) ) ? woocommerce_price( $from ) : $from ) .' Retail </del>  | </div><div class="live-colst">'.( ( is_numeric( $to ) ) ? woocommerce_price( $to ) : $to ) .'Our Price</div>';
      } else {
        $to = $product->price;
        return '<div class="live-colst">' . ( ( is_numeric( $to ) ) ? woocommerce_price( $to ) : $to ) . 'Our Price</div>';
      }
   } else {
     return '<div class="live-colst">0 Our Price</div>';
   }
}