$price_beg = 300; //Begin prijs
$percent_upgrade = 1.04; //Hoeveel procent de beginprijs duurder wordt. 1.00 = 100%;
$times_upgraded = array(0,0,0,0,0); //Hoevaak er al geupgrade is
$upgrade_percent = array(1.08,1.04,1.08,1.04,1.04); //hoeveel  procent er bij komt per upgrade
$values_before = array(0,0,0,0,0); //De values van de dingen die geupgrade worden.
$money = 0; //Geld


//CASE POSTED
if(isset($_GET['upgr'])):
	if($money-($price_beg*$percent_upgrade^$times_upgraded[$_GET['upgr']])<0):
		//NOT ENOUGH MONEY//
	else:
		$money-=$price_beg*$percent_upgrade^$times_upgrade[$_GET['upgr']];
		$times_upgraded[$_GET['upgr']]++;
		//DATABASE HANDLING//	
	endif;
else:
	//SHOW HTML//
endif;