Query Problem - Show posts within category 'x' that have a custom field between 'y' and 'z'

Question

I'd like to display all posts within a given price range. For example: When a user inputs 100 and 1000 (in two separate form fields) - my site will display all posts that have a custom field called price that has a numeric value between 100 and 1000.

Here's the catch:

I'd like to integrate this with the Multiple Category Selection plugin (http://wordpress.org/extend/plugins/multiple-category-selection-widget/)

Here's the code that the Multiple Category Selection plugin is creating for me:

<form action="" method="post" class="wpmcsw">
<input type="hidden" name="ajax_url" value="http://rentscholar.com/wp-admin/admin-ajax.php" id="ajax_url" />
      <input type="hidden" name="ex_cats" value="" id="ex_cats" />
      <input type="hidden" name="default" value="" id="default" />
      <input type="hidden" name="blank" value="all" id="blank" />
      <input type="hidden" name="order" value="default" id="order" />
      <input type="hidden" name="mcsw" value="1" id="mcsw" />    
      <div class="select_wrapper">
    <select name="wpmm[]" >
    <option value="0">Parent Category</option><option  value="8">Child Category One</option><option  value="9">Child Category Two</option></select></div><input type="hidden" name="mmctype" value="in" />
        <input type="submit" value="Search" /></form>

Answer 1

May this code help

$args = array(
    'cat' => 'Category id'
    'post_type' => 'post type',
    'meta_key' => 'enter your metakey',
    'orderby' => 'meta_value_num',
    'order' => 'ASC',
    'meta_query' => array(
        array(
           'key' => 'age',
           'value' => array(min price, max price),
           'compare' => 'IN',
       )
    )
);
$query = new WP_Query($args);

$query will contain an Array of post objects.

Reference:

https://codex.wordpress.org/Class_Reference/WP_Query