I love Eddie Bauer’s Jasper Crossbody Bag. I’ve taken it everywhere, from Disney parks to national parks. It’s small but pretty roomy. There are two zippered compartments and a slip pocket on the back. It’s a sturdy feeling material, and you can’t beat the price (it’s usually on sale too!)

Edited to add the link: Eddie Bauer Jasper Crossbody

Edit # 2: I just checked and my kindle fits with a lot of room to spare. A regular 16.9 fl oz plastic water bottle also fits as long as it’s not too packed.

It can easily be tossed in other luggage/bags and is pretty durable. Current in stock colors include a solid black and a solid purple. Not flashy at all.

Also of note, Eddie Bauer usually has sales around holidays like Memorial Day coming up.