The constructor AutoPrice.APItem(int, float, int, int, int)

...
public class AutoPrice extends JavaPlugin {
	public class APItem
	{
	    public int 		MaterialId;
	    public float 	PlSalesPrice;
	    public int 		PlSalesTotal;
	    public int 		PlPurchasesTotal;
	    public int 		TransactionMaxQty;
	}
	public ArrayList<APItem> APItems = new ArrayList<APItem>();

    public APItem GetAPItem(int Id) {
    	for (APItem I : APItems)
    	{
    	   if (I.MaterialId==Id) { return I; }
    	}
		APItems.add(0,new APItem(0,0,0,0,0));
    }
    public float GetDefaultPrice() {
    	return	1;
    }
    ...