Checking price based on zip code

zip-pricing.php

$zip = '00001'; // $zip can be populated by form submission

$pricing = $array(
  // zip => price associated with that zip
  '00001' => 10,
  '00002' => 15,
  '00003' => 20
);

// check if zip exists within array, and return the matching price
if ( in_array( $zip, $pricing ) ) {
  return $pricing[$zip]; // returns 10
}