Massive Stripe Update Help - Plan to Prices (~2019 version - present)

foreach (var subscription in stripeCustomer.Subscriptions)
{
  monthlyCost += subscription.Quantity * subscription.Plan.Amount ?? 0;
  if (string.IsNullOrEmpty(billingInfo.Subscription.PlanName))
  {
    billingInfo.Subscription.PlanName = subscription.Plan.Nickname;
  }
}
billingInfo.Subscription.MonthlyCost = monthlyCost / 100;

foreach (var subscription in stripeCustomer.Subscriptions)
{
  foreach (var item in subscription.Items.Data)
  {
    monthlyCost += item.Quantity * item.Price.UnitAmount ?? 0;
    if (string.IsNullOrEmpty(billingInfo.Subscription.PlanName))
    {
      billingInfo.Subscription.PlanName = item.Price.Nickname;
    }
  }
}
billingInfo.Subscription.MonthlyCost = monthlyCost / 100;