When you shop Greenfire you're paying for early access and rarity. Since they import stock rather than breed it you have access to established breeds. You also have it at a cost that's lower than importing it yourself would be. But the rarity is rather artificial and isn't going to last long.
If you wanted Bresse in 2017 you had to pay ridiculous prices. Today's prices for the breed are still high, but much lower than they were. If you order from Greenfire you're getting what you order. If you order from less reputable sources you might get Bresse that have been crossed with leghorns or lower quality eggs. But there are so many breeds to chose from that going for the rare and exotic is probably only necessary if you're either bored with the chickens you have or if you plan on selling hatching eggs yourself next year.
If you're bored there are cheaper ways of revitalizing your interest in chickens. Start a breeding program, swap eggs with other hobbyists, or volunteer as a 4-H leader for kids with the poultry project. While you're doing that the early adopters will be increasing the number of the rarer chickens available. Breeds like long crowers may never be popular enough that you'll find them at Cackle, but they will get less expensive as more people have them.
If you plan on selling hatching eggs, don't plan on the market being the same next year. First, until you've established a reputation you probably can't charge premium prices. Second, there's a lot more required to sell hatching eggs than than there is to sell eggs for baking or breakfast. Third, depending on how many others have the same idea your rare breeds may not be rare any more. At this point it's more business than hobby, and business is riskier. You'll still be able to sell hatching eggs, but probably not at prices that will allow a dozen eggs to cover your monthly feed costs.