Adding a bulk discount to ubercart without adding a new module
After digging through various hooks and trying different things, this is what ended up working for me, which was actually pretty simple in the end.:

function hook_cart_item($op, &amp;$item) {
    if ($op == 'load') {
        if ($item-&gt;nid == xxx &amp;&amp; $item-&gt;model == 'xxxxxxxxxx') {
            if ($item-&gt;qty &gt;= 100) {
                $item-&gt;price = round($item-&gt;price * .65,2);
            } else if ($item-&gt;qty &gt;= 25) {
                $item-&gt;price = round($item-&gt;price * .75,2);
            }
        }    
    }
}