I used to buy indiscriminately from Amazon. If Amazon had it, it was the best price. Why bother shopping around?
I've been bitten multiple times now with ordering something only to realize some reseller has jacked up the price and I didn't notice.
(e.g. buy baby wipes for $10, later re-order same baby wipes and think "hm, $18.50 seems higher than I remembered. Oh well, I need baby wipes!")
So now I shop around for everything. Since Amazon is "forcing me" to shop around, I've started to exclude them out of spite.
I get it, it's capitalism. If some Amazon reseller (including the "fulfilled by Amazon!" resellers) dupes me, I'm the sucker. Amazon's not to blame for capitalism. But... I still blame them. :)