[Sisom]

Well, from that we can deduce that the second part isn't producing anything at all on screen, so it must be the first part which produces the dollar sign:

<font class="ProductPrice">{include file="currency.tpl" value=$product_links[cat_num].taxed_price}</font>

The value of the price comes from
$product_links[cat_num].taxed_price
and this is fed into currency.tpl, which produces the dollar sign (presumably).

I'm not too sure how exactly $product_links[cat_num].taxed_price pulls the product price through, but somebody else here is sure to have much more experience than I with this - can anybody else help?