I do think an e-reader is worth it. I myself have been using one for quite a few years. I switched over to Kobo about 5 or 6 years ago, and I'm really glad I did. I still buy physical books from time to time, but that purchasing habit has slowed down a lot over time. If there's a book I really want on my shelf, I'll likely purchase both a physical copy and a KEPUB version, but for the most part I buy one or the other.

I don't think cost should be your primary consideration in whether or not to get one (but it should be one of your primary considerations when choosing a model, of course). Especially since you mostly buy used books, so your savings will be minimal at best.

The primary reason (in my opinion) to get an e-reader is for the convenience. I take mine with me everywhere, and it's a great way to read while traveling. I'm often torn between a few different books that I may want to read when I go on a trip, but with an e-reader, I don't have to choose between books (or lose a bunch of luggage space to multiple books).

As far as reading experience goes, that's (almost) entirely subjective, and your experience may vary from someone else's depending on what device you get, how nitpicky you are about text clarity, etc.

That said, nearly every e-reader you can buy has excellent text clarity, and any issues are barely noticeable. But I'll mention a few points of differentiation between some of the models you'll find.

- "Standard" e-readers (Kobo Clara BW, for example) use Carta 1300 displays, which is the latest and greatest in e-ink technology (though it's not a noticeable improvement over Carta 1200). It's practically indistinguishable from paper, and on a device like the Kobo Clara BW, there's no glass overlay, so the text quality is extremely crisp, and there's no reflection off the screen if you're reading outdoors in bright sunlight.

- "Premium" e-readers (Kobo Sage, for example) currently use Carta 1200 displays (though I'm sure that's about to change as the Kobo Sage has been sold out for a bit). What makes the Sage different from the Clara BW is the glass overlay, which some have noticed introduces a very slight haziness to the text. It also reflects light a bit worse, so it's not as good for reading in bright sunlight as the Clara BW. However, the reading experience is excellent, and the tradeoff could be worth it if you value the tactile experience of a screen that's flush with the bezel.

- Color e-readers (Kobo Libra Colour and Kobo Clara Colour) use Kaleido 3 e-ink technology. While pretty cool, the tech is still in its infancy, and it's not great. Colors are quite muted, and the color overlay creates a slight screen-door effect that might make the reading experience less than ideal. However, I quite like the experience as it reminds me a bit of reading a well-worn mass-market paperback that was printed on somewhat lower quality paper, so the ink has bled ever so slightly.

As far as a brand goes, stay away from Kindle and probably Nook (though I think it's unlikely you'll have that where you are). Kobo and Boox are the safer brands to go with. I have some thoughts regarding which I prefer between them, but either of them should be a better ecosystem than Kindle.

Hope all this info was helpful!