Hi,
I am now proving the correct patch now. (disregards the previous patch)
If you are using "default" layout for product details page, then the file you need to make is this:
ROOt/templates/<yourjoomlatemplate>/html/com_virtuemart/productdetails/default.php
If you are using "flexv2" layout for product details page, then the file you need to make edit is this:
ROOT/templates/<yourjoomlatemplate>/html/com_virtuemart/productdetails/flexv2.php
Find this expression:
number_format($this->product->prices['salesPrice'], 0, ',', '.');
And change it to;
number_format($this->product->prices['salesPrice'], 2, ',', '.');
Then you should start seeing the "add to cart" button even though the product price is lower than 0.5
But this time you will lose the ability to show the "call for price" feature when the product price is 0.00 though. I hope you don't have any product with the price of 0.00
Regards.
Forum Support.