Think of Amazon and how their changes their prices every few minutes, only the other week I ordered something then it dropped $5. I'm not entitled to compensation. And its not a lottery, the price you see is the price you pay should you choose to buy. Customers were complaining the price was too high, and so it was lowered. If we all tried to set a price at once or kept it level or moved it up and down willy nilly then we'd get nowhere. 467,149 cooks spoil the broth.
Last week demonstrated the Bitmain price to be a lottery for sure, the variable being which day/hour you purchase!
I've ordered many an item from Amazon, and the price variation is very small, though admittedly fun to shoot for the low. $50 out of $420 isn't small! Multiply by two and it's a major hit. Purchase by any other means at any mainstreet store, and you'd receive a refund for the difference! Of course, by your opinion, Bitmain should be exempt (must be nice to have your financial resources).
amazon and others show you
what they want YOU to see, and believe me, so many of us are overpaying...
Example#1: I was shopping on AMZN for turbotax home (because Intuit crippled Deluxe). price was $79 one day, then $80.84 once I "searched" twice for the same term-I guess they thought that I am hooked..I skipped. Same day from another computer-$48. Amazon is trying to make you pay extra ALL the time and they have lots of tools.
example#2: Every freaking time in the years past when I tried to buy an airplane ticket, in the last minute expedia tried to say that they misteriously run out of this specific ticket/price-would you like to pay $10 more. I ALWAYS canceled their "enhanced" ticket in such cases, so they ask less recently, but someone is either too gullable or don't care-so they continue.