    public static final String LEVEL_TICK = "tick";

    public static final PriceLevel TICKET = new PriceLevel("tick", "tick", -1);
    public static final PriceLevel MIN1 = PriceLevel.valueOf(LEVEL_MIN+1);
    public static final PriceLevel MIN3 = PriceLevel.valueOf(LEVEL_MIN+3);
    public static final PriceLevel MIN5 = PriceLevel.valueOf(LEVEL_MIN+5);
    public static final PriceLevel MIN15 = PriceLevel.valueOf(LEVEL_MIN+15);