I think the giant craze is...well, crazy! $500 for any fish that could die a month after getting him...well, that's insane! Funny how a breeder will increase price on an unusual betta in hopes that their "unusuallness" (or outright deformity!) will be thought of as unique, thus substatiated! What is even more pathetically sad, is that there will be at least 1 buyer who will say: "wow! How rare and unique! I am so lucky to have him!"
Although, he is the first butterfly giant that I have seen so maybe that is a rare combination :)
Vizja13: I am glad that I could help point you towards the right direction. And, though I feel strongly about buying local fish (from USA), my suggestion was a bit more complex than that. If the bettas you were contemplating were better looking and followed IBC (International Betts Congress) standards, I would have said "Go for it!"
Honestly, there are some Thai breeders that are awesome: aquastar71, farmfish66, phusit, interbettas...just to name a few! I tend to look at individual bettas and decide from there. Also, many breeders have specific lines which they excel at while their other lines might be newer, a work in progress so to speak. For instance, Interbettas has some gorgeous copper and copper/gold and copper/gold/gas bettas....but their yellows and oranges still need some work.
I steered you in the direction of Alex/Polukoff based on the pair you were contemplating. I recently purchased 3 blue/purple mustard bicolors HM females from him and they are outstanding! Even though he and his girlfriend, Rachel, usually have a few listings on aquabid, they sell majority of f'ish through facebook, word of mouth, and the classifieds on this forum. His sale thread on here is: My fish for sale!