[Eric]

It's pretty much the same way as the price, except simpler:

<?php
function merchant_title($merchant) {
    $merchant = strip_tags($merchant);
    return $merchant;
}
?>

<title>[category.name] | <?php if (@$_GET['merchant']) { ?> Provided by <?php echo merchant_title($_GET['merchant']); ?> | <?php } ?> </title>