But what do you mean by purchasing from Amazon? Directly from an Amazon warehouse, but not FBA (fulfilled by Amazon, from a 3rd party seller)? Or from a 3rd party seller who sells on Amazon but ships themselves? The latter is made up of hundreds (thousands?) of sellers, many of whom also sell on Ebay, AbeBooks, Alibris, etc. Many are actually "local brick & mortar" stores, which should be encouraged though Amazon takes their cut from these sales.

Thriftbooks, whom evidently so many like, sells through Amazon and Ebay as well as their own site.

There are so many potential issues to go into. New books from Amazon direct these days seem more likely to be damaged than they used to. At one time they were plastic wrapped and packaged carefully, now not at all - my experience. Just thrown loose in a box and left to slide around, so the covers are scratched up. Many third party sellers describe their books well and package carefully, and are a pleasure to deal with. Many more are just in it to make a buck because Youtube told them they could, and overgrade their books so a VG book is junk, missing the dustjacket, dirty, ex-library, etc. Amazon encouraged this behavior by re-defining their condition guidelines a few years ago so you don't know what you're likely to get now. This was to support the mass sellers of ex-library books and reject books, and this really damaged the on-line book buying experience while maximizing the profits of the mass sellers, also maximizing Amazon's cut.

Thriftbooks packaging is absolutely terrible, so if you order a hardcover in my experience it will most likely be damaged in shipping. Paperbacks tend to fare better because they are lighter and corners are not as vulnerable to getting "bumped". Any seller that ships in thin plastic with no other protection doesn't care about the books, so be warned. There are many of them, another mass-seller example is Betterworldbooks.

My refund rate from the mass sellers is greater than 50%, and I only order VG or better, and the listings cannot state "ex-library". Again the new Amazon guidelines which the online make-a-buck sellers have adopted allow ex-library to be listed as Very Good. Which is 100% BS, by the way. Not that I have an opinion on it.