I got mine as a package (new, 300+ and 375+) on ebay for $230 or so, Only really needed the 375 for the Boost Timing Retard, but I can't complain about getting a bunch of other features too.
Prior to that I just had the 300+, which that ignition box (my other 300+) is now going on my friend's Supercharged 318 powered Mazda RX-7