eBay

@8th-note  nailed it btw....

Paying around 15% or so to achieve an honest auction value for an item is a much better alternative in my experience.  

At the end of any day, eBay is a 24/7/365.25 auction at its' core.

As is Audio Mart, and the plethora of others for that which boats your float...;)

And shipping frequently becomes Your Problem.

15% is the price of admission to their vast buying audience and site logistics.  Seems fair enough to me.  I have bought and sold a lot of Tubes (best site to sell on) , CD’s and LP’s  with great success on eBay.  Higher priced items like components I sell on another site to avoid the high fees.  

OP, have you talked to eBay?

Yes, I have talked with eBay and all they say is this is what they charge. No real explanation, other than that. 

"eBay didn’t charge a fee on shipping and the last time I bought something, they didn’t charge me a fee on the tax."

- that is because the seller pays the fees to eBay, not the buyer, unless it is embedded in the "Buy it now" price by the seller.

"15% is the price of admission to their vast buying audience and site logistics." - "overall eBay charge 15-16 percent fees and tax every item I sold " - " the sad part people don’t understand how  eBay charges both ways seller and buyer seller pay fees and tax buyer pay only tax"

- don't know where you all are getting this information, eBay charges 13.25% selling fee.

"No real explanation, other than that"

- why would you think they owe you an explanation? One either uses their business or doesn't.