We've seen expensive time and again, but this particular Mustang carries a price tag that would make a high-bidder at Barrett-Jackson blush. You can own the very first 1964.5 Mustang convertible built and possibly the first Mustang ever sold for only $5,500,000.

Yikes. Seem steep to you? Fret not, buyer; a purchasing plan is available. Should you be willing to put $1,000,000 down, this pony car can be yours for $42,064.26 - a month!

(Click through for more on this steeply-priced 'Stang)

With 1965 Shelby GT-350s selling at auction for prices upwards of $300,000, what's the big deal about this car? After all, it's just a convertible, equipped with a 260 cubic-inch V-8, three-speed automatic. Sure, it's got a Rally-Pac and a center console, but cars so equipped usually run around $40,000. Where's the extra $5,460,000 come from?

That markup stems from the fact that this is likely the first saleable Mustang convertible, and the first Mustang ever sold. The car carries a build date of March 9, 1964 - the first day that the fabled pony car rolled down the Rouge assembly line. Furthermore, the car was delivered on the evening of April 16, 1964 - the night before Mustang sales were supposed to begin across the country.

Still, that's a high price just for those magic numbers, and it also makes us wonder - if one dealer skirted the sales embargo, were there others that did, too? That's entirely possible, but until authenticated sales receipts for other '64.5 Mustangs show up, this one's likely the first. Want it? Pony-up a bit more than five million and it's all yours.

+Classic Muscle Cars: 1964.5 Ford Mustang Convertible