I've never heard of Pirate King, but I've had my eye on Arkadia for about a year, and had the chance to play it once. It's definitely worth trying. You should have no trouble trading it if you don't like it. Not everyone has a B&N nearby.
This is what happens - you see it when a game goes up on Tanga for a cheap price, too. The trade value is inevitably affected. This happened with many other games that hit those cheap tables - Pizza Box Football, Rheinlander, Knights of Charlemagne, Niagara - all that stuff that was under $5 (sometimes just $1) at B&N or somewhere else. Just a fact of life.