I disappeared for a few months, and when I came back, I started noticing that dubloons in shops and trades were selling for not even half of what they were when I was last on. Did I miss something? Did the Smuggler's Cove open up while I was gone, or are people just giving up on it ever coming back?

I noticed dubloons are worth less now, too. I've been getting them quite frequently from Anchor Management and occasionally from Coltzan's Shrine. Perhaps that's something to do with it?

I think it's exactly what Bodhi said - they're so often prizes now that I think they just depreciated like mad...

Yes, I think Anchor Management has a lot to do with the deflation. Also the pirate morphing potions.  It doesn't matter to me though.  I sell everything I get as a prize. 

I have noticed but I think if I keep saving that Smuggler Cove will come back and I will be able to get that pesky SUAP. lol.

I usually save up the smaller dubloons to get a larger one. I'm working on getting a one thousand dubloon coin.

I'm in the same boat as all of y'all too. I've been getting them way more frequently than I used to, and I don't even remember when the prices really started to go downhill. I don't want to look a gift horse in the mouth, because regardless of how little they sell for it's still a profit! Just weird to see them so cheap now. 

Somewhat related, the cost of training-dublooms, codestones, red codestones-- in general is down too. It might have to do with the battle dome being less than it was before.

I have definitely noticed the red codestones have gone down in price.  As far as the dubloons go, 50 and 20 dubloon coins are being given out like candy from anchor management and coltzan's shrine, hence the drop in price.  As others said, anything is still profit, but yes, they are much cheaper.  Supply and demand, like every else in neopia.  Treasure chests are VERY cheap now.  I should have sold mine when they were going for 25,000 nps.  Now you can get them for 7,000 or less.

Now that chests are so cheap, I'm always tempted to open mine because it doesn't seem like much of a loss. One bag of Candy Pirate Earrings later and I always regret that decision. I just know that the one day I don't open it will be the day I almost had an MP or similar!

I've opened like 10 of them on the last few months, and nothing good ever comes hahahaha, on the dubloon thing, I think is because of the dailies, i find it interesting though because I wanted dubloons for my gallery, and got the 1000,200,100,50 for a very good price :)

Today I got D2 from Coltzan and D50 from Anchor.

Yes, I have so many 20 and 50 dubloon coins, but somehow I can never get the 5 dubloon coins I need for training. Grr... They had a rapid decrease around December, I believe, but I couldn't say why for sure.