My general rule with Amazon, at least for any costly purchase, is to choose items that are "sold by" or "fullfilled by" Amazon.
You won't find an iPad "sold by" Amazon. They want you to by a Fire.
But there are quite a few iPad sales being "fulfilled by" Amazon. That means that the item is in an Amazon facility, and is packed/shipped by Amazon. It also means that Amazon's standard 30 day return policy applies, so if you get an item that is DOA or damaged, they'll take it back no-questions-asked AND pay the return shipping.
I would recommend buying direct from Apple, but given you have the Amazon credits -- I would not hesitate to buy any of the offerings that say "fulfilled by" Amazon.