In the jinja2 file, you can set it like this…
<td class="rt">{{ "X {:,.2f}".format(doc.YOUR_FIELD) }}</td>
The X is your [optional] currency symbol and I have left the comma to separate the thousands with a comma, but if you don’t want that, then just leave it off ({:.2f} will create 1000.00 instead of 1,000.00)