At the moment i am trying to get the product price including tax in a php file for my product feed. I have this code at the moment:
$_product = Mage::getMode
You can get a helper-instance in any file using:
Mage::helper('tax')
Your full code is:
$_product = Mage::getModel('catalog/product')->load($productId);
$_priceIncludingTax = Mage::helper('tax')
->getPrice($_product, $_product->getFinalPrice());
Thanks @Alex:
If the product has FinalPrice special price is the final price of the product to access the most serious tax base price:
$_product = Mage::getModel('catalog/product')->load($p->getId());
$_specialPriceIncTax = Mage::helper('tax')
->getPrice($_product, $_product->getFinalPrice());
$_priceTax = Mage::helper('tax')
->getPrice($_product, $_product->getPrice());