The payment system isn't working at Code: https://instagress.com so until they fix it they are letting anyone use it for free. Its been down for nearly a week already so go take advantage of it while you can.
Good marketing trick. Win win for both users and instagress. I am sure couple of the test users will be buying it when the payment system is up.
Gave it a go, having good results. It definitely is a great marketing trick, although they haven't responded to my email