If you wish, it's your choice to keep your wish to yourself or make effort to fulfill your wish, believe it or not , if you have met an accident, you wont leave going to road in fear of facing accident, I also heard many peoples being charged by amazon, but you are just looking at the negative side of it, you are not looking how many peoples used credits/coupons and not charged at all ? how many peoples saved 90% of their bills, and a lot more can be said in this regard, and let me tell this to you, everyone knows this has never happened with google (I know this doesn't assures that it wont happens ever in future too) but if you are smart, you will knows several ways to tackle such situations!
and one more thing, buying or not buying is ultimately your choice regardless of your wish, your circumstances, your use case, and everything!
btw, believe it or not, I didn't like you posting this here, care to share who asked you to give your opinion here ? :-) or what made you feel it would be relevant to post here? google and amazon are different companies, and shouldn't be linked similarly (I intend no offense to you but expressing what I felt)
Really wish I could buy a coupon, mate. But after reading Amazon's TOS, the gamble is just too high; risking such an insane amount against a personal credit card. I've heard horrible stories where people had been charged hundreds after buying similar credit :\