I picked up a NOS early 1960's/1970's (circa 1969-1972) Sprint in Blue from an online jeweler called OLD WORLD JEWELERS, back in around 2002. I paid then something like $800 for it. It's really different looking and definitely early-70's in feel, which I find fun.
Recently, these things have been making a bit of a comeback by way of the new rash of "Vintage Watch Curators" that have popped up, including those peddling to Park & Bond (a high-end men's clothing and accessories website here in the US). Anyways, currently, you have to pony up $3000 for the watch that was $800 just 8 years ago.
A few things, I'll say about this, before people jump in with the perennial mantra of "its a solid investment, that you can appreciate AND watch appreciate in value". These watches were COMPLETELY forgotten for 3 decades, completely shelved because, honestly, there was little to no interest in them... jewelers were willing to take whatever they could for them just to get the money out of 'em. NOW, there's a bunch of "designers" and "curators" and "style experts" who JUST discovered their existence, and are trying to make a buck on their "finding". I think its a big sham. I love the watch, its funky, and its different, and it definitely is an acquired taste, but I'd NEVER pay $3000 for one. If I didn't like it so much, I'd sell it for that price tho.
In the same kinda way, I made a killing on my 1970 Blue Square face Zenith El Primero, which I bought NOS on ebay in 1998/1999 for $1200. I saw one in worse condition than mine (I put a tiny scratch in it about 10 years ago, no one would notice (or devalue it considering the overal condition and its vintage), otherwize she's flawless... but I KNOW its there and remember the event vividly) - for $11,000 at Tournneau's Used section... I almost did a backflip.

Bare in mind there were far fewer of the Zeniths than the Breitling Sprints, and the El Primero is 1/1000 made in that color, and has a place of importance as housing an original El Primero movement (the first Automatic Chronograph movement in history, beating out the Heuer/Breitling/Hamilton/etc... group by a few months with their Cal. 11). Seeing the El Primero for $11K seemed more than a little whacked out, but its more understandable than $3K for a Sprint.
All this Sprint talk has made me wanna update mine with a new strap and wear it more often.
Thanks for that.