It is as typographic error. Bear in mind that in the anglo-american world dot and comma have an opposite meaning concerning figures than in other ports of the world.
I once erroneously typed in a bid on a US-site german-wise and also got something of that kind. But was warned by the system....
That's the obvious explanation...note that the postage is also given as $1200.00! As you say, dot or comma in the wrong place.
(But the ideas of money laundering and spies are more fun )