Pioneer HPM-40 Vintage Speakers

In my day the holy grail of Pioneer speakers was the HPM-100 model which, I think, was the largest?  Frankly speaking you really don't see much of the "vintage" Pioneer/Sansui/Marantz receiver gear here, but eBay seems to have a large audience for that.  Best of luck!

The Audiogon BLUEBOOK for used equipment relates that a used pair of HPM 100 might fetch around $290 on average. Again, the BB average pertains to items listed and sold here, so methinks your target audience is eBay. I've bought a few receivers there with no issues. 

Pioneer made an HPM150 and an HPM200 also.  I'm old, I sold these at the very end of their retail life cycle.  
The 40's were a bit more balanced than the 100's, but both could get edgy.... I've never measured the 40's, but the 100's were about 90db sensitivity up to around 1k,  then rose 5 or 6 db above that,  the mids & highs were quite a bit hotter.... I never got the impression from the 40's that they were that far off.  
As far as selling,  if they look great, you'll sell them,  if you can find someone with a fond memory of these,  you'll get a decent price,  If not,  its another cheap speaker. They manufactured from 1976 to 1979.  I sold them in 79

i've owned both the 40s and the 100s; neither are highly-resolving audiophile pieces but are a lot of fun--big (if sorta overbright) sounding, cool aesthetics, and good for a mancave vintage system. $75-100 for the 40s sounds about right.

I would sell them for whatever someone was willing to pay me for them and not holdout for any more than that. They were my first pair of speakers from about 1979 or so and they are still with me, doing time in my basement. I hooked them up a few years ago for kicks and after listening for awhile realized that they really are lacking compared to so many of today's speakers. they really don't have any value in my book.