JSFiddle - React, Tailwind, and code Playground

JavaScript

function getSlotsIncPrice( oldSlotsCount ) {
// Получить цену увеличения слотов
	var slotsLimit = 155;
	var newSlotsCount = oldSlotsCount + 5;
	if ( newSlotsCount > 155 ) return 900000;
	var price = newSlotsCount - 25;
  /*
	for(var i = 25; i < newSlotsCount; i+=5 ){
		price += 5;
	}
  */
	return price;
}
console.log(getSlotsIncPrice(25));