We got a Kindle Kids Edition (NOT a Kindle Fire) for our son's birthday last spring when he was turning 8. I've seen them go for less than $100, including a yearlong subscription to the Amazon Freetime library. The Amazon library tends to make the very first book in many different series available, when he finds one he loves we check out the sequels from the library. I like the Kids Edition Kindle because they can't watch videos and it's easy on the eyes for reading. I think it's helped him move away from graphic novels and into more chapter books because the format fits better (although he still reads a lot of Big Nate on his Kindle).
We can also download ebooks from our library onto his Kindle. Seriously, this was all a lifesaver when the world shut down last spring.
We get a TON of books from our library, but we also use a Kindle Kids Edition (NOT a Kindle Fire). I've seen them go for less than $100, including a yearlong subscription to the Amazon Freetime library. The Amazon library tends to make the very first book in many different series available, when he finds one he loves we check out the sequels from the library. I like the Kids Edition Kindle because they can't watch videos and it's easy on the eyes for reading.
We also go to our local used book store when we find books we really love and don't want to return to the library.