title: How to format table fields as currency in org-mode
body: <p>I'd like to format fields in an org-mode table as currency
  - meaning with currency symbol ($) and commas as thousands separators.  I've been using $%.2f to get e.g. $1000.00 but how to get the comma separators e.g. $1,000.00 ?  I've RTFM but perhaps I am too dense to get it.  Either calc or elisp  formula is fine.  See sample table below:</p>
  
  <pre><code>| Item     | Quantity |  Price |      Ext |
  |----------+----------+--------+----------|
  | Widget 1 |       10 | 100.00 |  1000.00 |
  | Widget 2 |        5 |  50.00 |   250.00 |
  | Widget 3 |        1 |   5.00 |     5.00 |
  |----------+----------+--------+----------|
  |          |          |  Total | $1255.00 |
  #+TBLFM: $4=($2*$3);%.2f::@5$4=vsum(@2..@4);$%.2f
  </code></pre>