Going to play a little devils advocate here. They are giving you a phone to test for a dollar when has apple done that? Apple doesn't even have enough stock to keep up with demand for like at least a couple months when they launch a new phone at regular price so you should be used to waiting for a phone.
Don't most carriers and Apple have a 14 day no quibble return policy. Many have used that here for years. Whilst your only charged $1 up front for the Samsung test, they pre-authorise payment in case you decide to keep it. As soon as you go over the test period you are billed.
That's not massively different to paying for your device up front, using the device and returning it within your 14 days and getting your money back / refunded.
Either way - you get far better service than Europe where we do not have this 14 day returns policy or trials.