add a shopping cart button to a list of nodes

Question

I am creating a module that display a custom add to cart button for each item i fetch from DB. ( I don't want to use ubercart but rather a custom simple cart).

So my code looks like this: mycustom_page() {

$sql = "SELECT nid from {nodes} n WHERE n.type = :type AND n.status = :status";
$result = db_query($sql, array(
'type' => 'products',
'status' => 1,
));
foreach($result as $row) {
$node = node_load($row->nid);
$page[query'][] = node_view($node, 'teaser');

return $page;

}

this will return a list of nodes of type products. All I need now is to add a form with a add to cart button and a callback with add to cart feature.

How do I add a form to each node? Also I need if is possible to display and handle the node fields separately inside the foreach.

Many thanks