MVC自定义验证最小价格

我有一个项目。我需要一个自定义验证找到最低价格。首先我所有的模型都在这里;

public class ReservationModel
{
    [Required]
    public DateTime BeginDate { get; set; }
    [Required]
    public DateTime EndDate { get; set; }
    [Required]
    public double Price { get; set; }
    [Required]
    public string EmailAddress { get; set; }
    public Guid ApartId { get; set; }
    [Required]
    public int Guest { get; set; }
    public string ApartName { get; set; }
    public string City { get; set; }
    public string Country { get; set; }
    public string AddressLine1 { get; set; }
    public string AddressLine2 { get; set; }
    public string ApartDesc { get; set; }
    [Required]
    public string FirstName { get; set; }
    [Required]
    public string LastName { get; set; }
    public string CategoryName { get; set; }
    public double MinAmount { get; set; }
    public string ApartImage { get; set; }
    public string CheckInTime { get; set; }
    public string CheckOutTime { get; set; }
    public int DayOfReservation { get; set; }
    public int ReservationGuestNumber { get; set; }


}

我想在MinAmount中使用这个验证。我有动态价格。例如分开价格300美元。我想要的最小金额必须是300 X 25/100 = 75美元。验证错误为客户端写入50美元或低于75美元。那么如何创建我的自定义MinPriceAttribute??谢谢您的回复。