I know it seems a little shocking at first, but consider that Platinum Blonde, like many Canadian Bands from the 80's (Spoons, Glass Tiger, The Box) released and sold millions of albums on vinyl and cassette, but few on CD. The record companies made limited runs of CD's back then due to it being an unproven technology.
Next, I'm not sure where the buyer is, but if he's in the US, then this is even more rare for him, as Canadian artists received limited distribution South of the border with the exception of border towns.
Third, I am a Platinum Blonde fan who dropped $22 on their Greatest Hits CD two years ago (okay, so that's less than $56 US, but a fan will pay that much.) Speaking of which, I just sold a collection of 15 Cure cassettes to some guy in France on e-bay for $52 US. I still love the band, but had upgraded all the tapes to disc.
Now, let's see if Secrets of the Alibi, Snow In June or Neptune climb that high, eh Mike?