So we make  query to get node ID from particular product ID

$query = new EntityFieldQuery;
        $query->entityCondition('entity_type', 'node', '=')
        ->propertyCondition('type', 'product_display')
        ->fieldCondition('field_product_reference', 'product_id', '1092', '=')
        ->range(0, 1);

If node is present, we do the array building

To make square brackets in JSON, which is basically array in JSON you need to write array twice. So make it
array(array('something'....

$data = json_encode(array(
    'list'=>array(array('commerce_price_aud' => array (....

Although there is an article here about it http://blog.ampli.fi/creating-drupal-7-nodes-with-php-via-the-restws-ap…
I will copy mine code I used to test, just in case.

Things to watch out for is NOT to include JSON suffix, when using CURL

For some time this has been in drupal 7, ported from drupal 8
https://www.drupal.org/node/2307505

But not really mentioned much. Its a nice feature where you get directly in your html template file names you can use for changing html.
Looking like this

There are different methods and bunch of modules to ajaxify links in drupal. There are different solutions with code, like this one
https://www.drupal.org/node/2046693
and there are more simple I would add, like this one

Having custom template or function to preprocess your custom form in module has few tricks.

First you need to define it in form

$form = array();
$form['#theme'] = 'my_form_theming_function';
....

then define hook_theme

When changing weight of element in array, it is not enough to just change weight, #sorted must be set to FALSE so elements are resorted.

$variables['form']['element']['#weight'] = -10;
$variables['form']['element']['#sorted'] = FALSE;

Took time to find out this one. To set title or label for a fivestar form field you need to add
'#title' => t('Your rate'), to your code, so it should go like.

Use Mailchimp's RSS-Driven Campaign as it is refered to here. So make a view outputting RSS and use that.

http://kb.mailchimp.com/campaigns/rss-in-campaigns/create-an-rss-driven…

You can preprocess nodes and fields with hook_preprocess_field hook_preprocess_node, but when it comes to beans, you need to use different approach, hook_preprocess_bean doesn't exists. So to do this, you need to use this