How to add currency (TMT) to Commerce? Turkmenistan Manat is missing from Drupal Commerce list - how to add it to 7.x?
Per the commerce.api.php file, there is a document hook which allows you to add currencies.

function hook_commerce_currency_info() {
  return array (
    'CHF' =&gt; array(
      'code' =&gt; 'CHF',
      'numeric_code' =&gt; '756',
      'symbol' =&gt; 'Fr.',
      'name' =&gt; t('Swiss Franc'),
      'symbol_placement' =&gt; 'before',
      'code_placement' =&gt; 'before',
      'minor_unit' =&gt; t('Rappen'),
      'major_unit' =&gt; t('Franc'),
      'rounding_step' =&gt; '0.05',
    ),
  );
}


http://cgit.drupalcode.org/commerce/tree/commerce.api.php