Well, let's look at this in more practical terms, then.
Buchla 285e = $1599 (wrong format)
Club of the Knobs 1630 clone = EUR 970 (wrong format)
Synth-werk's 1630 clone = EUR 1950 (also the wrong format)
Encore Frequency Shifter = $399 (but it IS Eurorack)
Modcan Dual FS = $349 (and two channels...this is the closest in terms of price vs function to the Behringer)
Synthesis Technology E560 = $339 (not purely an FS, though)
Tokyo Tape Music Center 185 = $580 (clone of the original Buchla 185)
Cwejman FSH-1 = $680
...and the Behringer comes in at $199. But with the possible exception of the Buchla 285e, you're dealing with small-run devices, which increases the cost. Behringer appears to be using their usual board fab methods, though, and it's far cheaper to have boards stuffed via automation and wave-soldered.
And in truth, if I could have any frequency shifter I wanted, I'd try and source the mid-70s standalone unit from 360 Systems. Of all of them that I've heard or used, IT is the best...with any cloned Bode-type coming in next. But if you've ever tried to find one of those 360 Systems ones, you'd know that it was something of a fool's errand to locate one. They almost NEVER appear on the used market.