Played with one at length when a pair of factory reps from Blaser/Mauser were over here and on their way to the SHOT show a year or so ago. They are certainly a cut above what one typically finds on the shelves here.
The basic 03 retails for about $ 2750. A second barrel, bolt head & magazine is maybe another $ 1000 ( and is super easy to change ... maybe 30 seconds....wood upgrade to Grade 5 ... another $ 1000.
Mauser original "Double Square" mounts for a 1" American scpoe tube are probably another $ 425 or so.
Also available in a true left hand ... and with a left hand stock on a right hand rifle. Every "option" is an added cost - and it does add up quick, just like on a good vehicle.
Not hard to lay down $ 5 or $ 6 grand for a really fine rifle with a pair of barrels in different calibers.