Sometimes you just need to get your hands dirty and start adding Drupal Commerce products programmatically. Luckily that is not that hard of an thing to do.

Create a Product entity:

       // Product       $product = commerce_product_new('product');       $product->sku = "PRODUCT-SKU";       $product->title = "Product Title";       $product->language = LANGUAGE_NONE;       $product->uid = 1;       $product->commerce_price[LANGUAGE_NONE][0] = array(         'amount' => 10 * 100, // $10         'currency_code' => "USD",       );       commerce_product_save($product);

To set the product category (which is a taxonomy term):

       $product->field_product_category[LANGUAGE_NONE][0]['tid'] = 1; // 1 = the term id

To set the stock:

       $product->commerce_stock[LANGUAGE_NONE][0]['value'] = 1;

To set VAT / Sales Tax:

       $product->commerce_price[LANGUAGE_NONE][0]['data']['include_tax'] = "vat"; // "vat" = machine name for the tax       $product->commerce_price[LANGUAGE_NONE][0]['include_tax'] = "vat"; // "vat" = machine name for the tax

If you modify any of these fields, remember to run "commerce_product_save($product);" at the end.

To create a Product display for your new product, you need to use the previously used $product variable.

       // Product display       $node = (object)array('type' => 'product_display');       node_object_prepare($node);       $node->title = "Product Display Title";       $node->uid = 1;       $node->field_product[LANGUAGE_NONE][]['product_id'] = $product->product_id;       $node->language = LANGUAGE_NONE;       node_save($node);