You will have to use two DrawStrings: one for the label ("computer table") and one for the price ("1500.00")
You can then use the same rectangle:
RectangleF rect = new RectangleF(10.0F, 10.0F, 200.0F, 30.0F);
StringFormat format = new StringFormat(StringFormatFlags.DirectionRightToLeft);
g.DrawString("Computer table", font, brush, rect);
g.DrawString("1500.00", font, brush, rect, format);