If you're buying the "in" coral, yeah, you're gonna pay a premium. No, I don't think we're getting ripped off.
Here's the deal. This industry, like all others, is supply and demand. If a piece is popular and uncommon, it's going to be expensive. If it's boring and grows like a weed, it's gonna be cheap. That's just the way of it. Sure I've payed alot for certain acros. Do I feel ripped off? No, not at all. I payed a price that was required to get the piece.
Now if the going rate for a piece is 50 bucks and someone is charging 150 for it, then yeah, they're ripping you off. As long as the prices are in line, though, its the cost of doing business. And to be fair, if a consumer is willing to pay it, they have every right to charge that price since this hobby is entirely a luxury. It's not like someone is charging 10 dollars for a dozen eggs or 50% above market for rent.
Don't like the prices, don't buy the item, but I'd be willing to bet someone else will or they wouldn't mark it at that price.