Add percentage to price during wpallimport [duplicate]

I have a wordpress site using wpallimport to import from suppliers, the price they provide is wholesale pricing. The structure is:

productcode  01-4231
statuscode  A
netprice  3.01
freestock  12

I wish to add a percentage of 20% to the netprice, what would the php function be? And should I place netprice in regular_price aswell as have the function?

$cost = $product->price; //Get product price
if($product->price > 0){ //If shipping fee needs to be applied
   $cost += 40%; //Add percentage
}