<appSettings>
...
	<add key="Secret_API" value="** ENTER YOUR SECRET API KEY **"/>
...
</appSettings>

PinService ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);

or

PinService ps = new PinService();

PinService ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);

// https://pin.net.au/docs/api/test-cards
// 5520000000000000 - Mastercard
// 4200000000000000 - Visa

var card = new Card();
card.CardNumber = "5520000000000000";
card.CVC = "111";
card.ExpiryMonth = DateTime.Today.Month.ToString();  // Use the real Expiry
card.ExpiryYear = (DateTime.Today.Year + 1).ToString(); // Not my defaults!
card.Name = "Roland Robot";
card.Address1 = "42 Sevenoaks St";
card.Address2 = null;
card.City = "Lathlain";
card.Postcode = "6454";
card.State = "WA";
card.Country = "Australia";

var response = ps.Charge(new PostCharge { Amount = 100, Card = card, Currency = "AUD", Description = "Desc", Email = "email@test.com", IPAddress = "127.0.0.1" });
System.Console.WriteLine(response.Charge.success);

// See https://pin.net.au/docs/api/charges#search-charges for more detail
PinService ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);

var cs = new PinPayments.ChargeSearch { Query = "", Sort = ChargeSearchSortEnum.Amount, SortDirection = SortDirectionEnum.Descending };
var response = ps.ChargesSearch(cs);
System.Console.WriteLine(response.Count.ToString() + " transactions found");
foreach (var r in response.Response)
{
    System.Console.WriteLine(r.description + " " + r.amount.ToString());
}

// See https://pin.net.au/docs/api/customers#get-customers
ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);
var customers = ps.Customers();

// See https://pin.net.au/docs/api/customers#post-customers for more detail
ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);

var customer = new Customer();
customer.Email = "roland@pin.net.au";
customer.Card = new Card();
customer.Card.CardNumber = "5520000000000000";
customer.Card.ExpiryMonth = "05";
customer.Card.ExpiryYear = "2014";
customer.Card.CVC = "123";
customer.Card.Name = "Roland Robot";
customer.Card.Address1 = "42 Sevenoaks St";
customer.Card.Address2 = "";
customer.Card.City = "Lathlain";
customer.Card.Postcode = "6454";
customer.Card.State = "WA";
customer.Card.Country = "Australia";

var response = ps.CustomerAdd(customer);

System.Console.WriteLine("Customer token: " + response.Customer.Token);

// See https://pin.net.au/docs/api/customers#put-customer
ps = new PinService(ConfigurationManager.AppSettings["Secret_API"]);
var customers = ps.Customers();
customer = customers.Customer[0];
customer.Card = new Card();
customer.Card.CardNumber = "5520000000000000";
customer.Card.ExpiryMonth = "05";
customer.Card.ExpiryYear = "2014";
customer.Card.CVC = "123";
customer.Card.Name = "Roland Robot";
customer.Card.Address1 = "42 Sevenoaks St";
customer.Card.Address2 = "";
customer.Card.City = "Lathlain";
customer.Card.Postcode = "6454";
customer.Card.State = "WA";
customer.Card.Country = "Australia";

customer.State = "NSW";
var customerUpate = ps.CustomerUpate(customer);            

// Refunds - Pin supports partial refunds
// https://pin.net.au/docs/api/customers#get-customers-charges

var refund = ps.Refund("INSERT CHARGE TOKEN", 200);
refund = ps.Refund("INSERT CHARGE TOKEN", 100);


// Lists all refunds for a particular charge
var refunds = ps.Refunds("INSERT CHARGE TOKEN");

// Card Token
// https://pin.net.au/docs/api/cards
// 5520000000000000 - Test Mastercard
// 4200000000000000 - Test Visa

card = new Card();
card.APIKey = ""; // OPTIONAL.  Your publishable API key, if requesting from an insecure environment.
card.CardNumber = "5520000000000000";
card.CVC = "111";
card.ExpiryMonth = DateTime.Today.Month.ToString();  // Use the real Expiry
card.ExpiryYear = (DateTime.Today.Year + 1).ToString(); // Not my defaults!
card.Name = "Roland Robot";
card.Address1 = "42 Sevenoaks St";
card.Address2 = "";
card.City = "Lathlain";
card.Postcode = "6454";
card.State = "WA";
card.Country = "Australia";

var respCardCreate = ps.CardCreate(card);

response = ps.Charge(new PostCharge { Amount = 1500, CardToken = card.Token, Currency = "AUD", Description = "Desc", Email = "email@test.com", IPAddress = "127.0.0.1" });
System.Console.WriteLine(response.Charge.Success);	


// Card tokens can only be used once.
// If you try and use it a second time, you will get the following message:
response = ps.Charge(new PostCharge { Amount = 1500, CardToken = card.Token, Currency = "AUD", Description = "Desc", Email = "email@test.com", IPAddress = "127.0.0.1" });
System.Console.WriteLine(response.Error); // "token_already_used"
System.Console.WriteLine(response.Description); // "Token already used. Card tokens can only be used once, to create a charge or assign a card to a customer."