$50 is a good price, but you'ld still have some work to do to make sure the speakers are all in good working condition. Sometimes the tweeters are dead on these old Pioneers.
I personally have nothing against someone making a quick buck by flipping thrift store finds on ebay. After all, it provides cash to fund the procurement of other vintage gear that I really do want to keep. You can't keep every nice item you run across, so why not sell some of it to fund your hobby?
You appear to be a professional ebay seller, so you may not currently have an interest in vintage gear other than the profit motive. If you continue to pursue selling vintage audio, you'll discover that most items you find are not in 'mint' condition and you've got to acquire the knowledge and skills to put them back in top shape. This is especially true with speakers. To restore their value so to speak...
Example, you'll run across a dirty-looking Pioneer hi-power reciever at the thrift for $20. You'll research it on ebay and find it's worth $500. You'll get it home only to plug it in a find that one channel is dead and it's only worth parts.
Now you're properly motivated to try and fix it. You'll take it apart, clean all the POTS and switches, blow the dust out, clean the interior, polish the face plate and all knobs put it all back together and viola! It works!
Then a funny thing happens... You no longer want to sell it.... You find yourself looking for a nice vintage set of speaker and a turntable to go with it. Then you're fixing up other amps and before long your garage looks like an electronics shop and you're wife is bitching about it. :nono: That's how you know you've arrived.
I don't think that some AKers realize how this site contributes to the appreciation of vintage gear. Sure these folks are sharing the knowledge, but they're also getting people like you into the hobby, thus expanding the community and the Karma. Vintage audio nuts aren't born, they're made.
Until then, my advice is to lay low around here, be polite, demonstrate that your questions are well thought out, that you've done some research not just gimme gimme gimme... and most importantly keep your ebay hobby to yourself. :yes: