I will point out that, in some cases, Amazon is carrying kindle versions of books with updated translations (and therefore not out of copyright).
For example, in the case of
The Count of Monte Cristo Amazon is carrying multiple versions. The most expensive version ($9.75 currently), is
this one from Penguin, which is the one (relatively recently) translated by the late Robin Buss. All of the prior versions, including the PG version, all use the 1846 anonymous translation. Of course, the Buss translation is vastly superior, and in my opinion, well worth both reading and owning (particularly if you are a fan of Edmund Dantes). You can read a small bit about the differences
on wikipedia.