If you have an early departure or late arrival at Tokyo's Haneda Airport, then Kamata is a good place to stay, as there are direct trains that get you there in less than twenty minutes. And if you're on a budget, and/or want a unique Japanese accommodation experience, then a good choice is this capsule hotel, well located and well appointed.
(As long as you're a man: like many capsule hotels, this one is male only.)
Arriving late at night, I took my shoes off at the entrance, checked in with the friendly staff (some of whom speak fairly capable English), collected my locker key, and headed up to the capsule floor. This was much more spacious than I expected: rather than just rows and rows of capsules, the floor was partitioned off into little booths with two capsules in each, providing (relatively) more privacy and space. If you do want your own space, there's one floor of tiny cabins that have a single capsule and a small desk and chair.
Changed into the nightwear provided in the locker, shorts and shirt in surgical-gown blue, I took the hotel's bright yellow towels and went off to the bathroom. This is also big and well-equipped: as well as the large central bath, part of it frothing away like a jacuzzi, there are two saunas (one very hot, the other even hotter) and two cold baths (one chilly, one icy) for the complete authentic Finnish-style experience. If you don't want to get naked with a roomful of Japanese men, each floor also has a shower room, which I assume affords a more private bathing environment.
What else? There are small lounges on each floor and a big one on the second, where you can read from the shelves of Japanese magazines or manga, zone out in front of the TV, or make use of the Wi-Fi. On the second floor there's also a cafe, where for a few hundred yen you can buy snacks, drinks, light meals, or a substantial-looking Japanese breakfast. And in the lobby there's a well-stocked store, which seems to sell mostly sake, as well as some snacks and other drinks.
Kamata really is a working town, not a sightseeing destination, so while there's not much to take pictures of, it's a good place to get a feel for everyday Japanese life. The hotel is between the town's two stations, a short walk from each, so there are plenty of shops, cafes, restaurants, bars, and a couple of supermarkets. Finding somewhere to eat will not be a problem.
I couldn't find a website, so if you want to book in advance it'll be on a booking website: rates look pretty consistent, at ¥3300 for a regular capsule, or ¥4300 for one of the cabins. I found this to be a fun place to stay, adequately comfortable and good value for the location and facilities, so if I need to stay near Haneda airport, I'll certainly come here again.