They lock in the price. I bought 3 bitcoins for $48.48, and shortly thereafter the price jumped up by a couple dollars. 5 days later, there was a charge in my b

They lock in the price. I bought 3 bitcoins for $48.48, and shortly thereafter the price jumped up by a couple dollars. 5 days later, there was a charge in my bank account for a total of $48.48.