What's wrong with my GET request? (Commerce Services, REST) I'm developing a mobile app to connect with my Drupal Commerce (Kickstart) store, using a REST server.

When I do GET: endpoint/rest/product it retrieves the products list 

&lt;result is_array="true"&gt;
    &lt;item&gt;
        &lt;revision_id&gt;1&lt;/revision_id&gt;
        &lt;sku&gt;TOT1-GRN-OS&lt;/sku&gt;
        &lt;title&gt;Tote Bag 1&lt;/title&gt;
        &lt;revision_uid&gt;1&lt;/revision_uid&gt;
        &lt;status&gt;1&lt;/status&gt;
        &lt;log /&gt;
        &lt;revision_timestamp&gt;1423972403&lt;/revision_timestamp&gt;
        &lt;data /&gt;
        &lt;product_id&gt;1&lt;/product_id&gt;
        &lt;type&gt;bags_cases&lt;/type&gt;
        &lt;language&gt;und&lt;/language&gt;
        &lt;uid&gt;1&lt;/uid&gt;
        &lt;created&gt;1423972403&lt;/created&gt;
        &lt;changed&gt;1423972403&lt;/changed&gt;
        &lt;title_field&gt;Tote Bag 1&lt;/title_field&gt;
        &lt;commerce_price&gt;
            &lt;amount&gt;1600&lt;/amount&gt;
            &lt;currency_code&gt;EUR&lt;/currency_code&gt;
            &lt;data&gt;                &lt;components /&gt;
                &lt;/data&gt;
        &lt;/commerce_price&gt;
        ...
    &lt;/item&gt;
    &lt;item&gt;
     ...
    &lt;/item&gt;


Everything looks fine. I can even GET endpoint/rest/product?status=1 and it does filter well.

I'm trying to filter by commerce_price.amount:

GET endpoint/rest/product?commerce_price.amount=1600

but it's not working. I have no problems filtering by a first level key, but can't access second level ones and so on. What am I doing wrong?
From what I understand, querying only works on entity properties. That is why status works, commerce_price is a field and won't work. Checkout Services Entity API, it may do what you're looking for. 

You may still be out of luck though. You alternatives will be to use services_views or write your own Services Resource.