StringOverrides doesn't change the text in DCommerce "Add to Cart" Button
The fields I was trying to change ended up being hard-coded into drupal commerce, such that string Overrides, and even the Commerce Cart Overrides modules didn't help me get done what I needed to do completely.

So...I applied the hook_form_alter() functions in the bartik theme, because I couldn't get them to work in a stand alone module, although from what I read this would be better practice and then you don't have to remember what you changed where if you want to change themes etc.

So, combination approach got done what I needed in the end. Have to say, overall documentation is pretty opaque for a relatively easy fix and from googling, a relatively around a common problem.

Code snippet that might help:

function bartik_form_alter(&amp;$form, &amp;$form_state, $form_id){
dpm($form_id);
dpm($form);
if (commerce_form_callback($form_id, $form_state) == "commerce_cart_add_to_cart_form"){
$form['submit']['#attributes']['title'] = $form['submit']['#attributes']['value']=t("Add to Inquiry List");
}
if(strpos($form_id, 'views_form_commerce_cart_form_default')===0){
$form['actions']['submit']['#value'] = t("Update List");
$form['actions']['checkout']['#value'] = t("Submit List");
}
if(strpos($form_id, 'commerce_checkout_form_checkout')===0){
    $form['buttons']['continue']['#value'] = t('Proceed to final list submission.');
    }
if(strpos($form_id, 'commerce_checkout_form_review')===0){
    $form['buttons']['continue']['#value'] = t('Submit your inquiry list');
    }


}