$wpdb query for price in custom field value

A classifieds list site have only 3 criterias when searching products: the common search, category and region (for ZIP, city or full address) It's not enough and I really need to include a basic price system, so users can set a price range before searching.

Looking at the theme files, I found the function for different queries, based in one or more of those criterias. The smaller is the query for only category, so I'll take it as example:

elseif ($s_for == ''  $s_cat !== ''  $s_to == '') {
$query = "SELECT $wpdb-posts.*
FROM
$wpdb-posts
INNER JOIN $wpdb-term_relationships
ON $wpdb-posts.ID = $wpdb-term_relationships.object_id
WHERE
$wpdb-posts.post_type = '$cc_post_type'
AND ($wpdb-postmeta.meta_key = '$cc_price' AND $wpdb-postmeta.meta_value LIKE '%$s_prc%')
AND $wpdb-posts.post_status = '$cc_post_status'
AND ($wpdb-term_relationships.term_taxonomy_id = {$s_cat})
GROUP BY ID {$limit}";
}

Product prices are stored in custom fields (cc_price), so I tried...

AND ($wpdb-postmeta.meta_key = '$cc_price' AND $wpdb-postmeta.meta_value LIKE '%$s_prc%')

...with a simple checkbox ($s_prc added to functions) with the value (just for testing purposes), but it doens't work, "query with no results". Is the query correct and I'm wrong in any other point?