Where to buy "hanten"?

Been to several onsen noticing the outer jacket People wear over their yukata. I managed to buy a yukata before but never been able to find the hanten I think it is called.

Any place in Tokyo that might sell it for not too expensive price? Not expecting to look in the touristy areas like Asakusa where things seemed a bit over priced...

Yanaka?

There are a chain of second hand stores called "Chicago" which sells second hand Kimono, Yukata and those outer jackets, beside many "normal" second hand clothes.

https://www.chicago.co.jp/

If you're looking for inexpensive hanten, they're often sold at so-called "town supermarkets" like Ito Yokado, Maruetsu, and Daiei in their clothing sections. However, these chains' branches tend to be a little farther out in the suburbs (though still reachable by trains from downtown), and they also tend to mainly be available in the fall and winter months, not so much in spring and summer

You'll probably also be able to find hanten at dedicated kimono shops, and maybe major department stores like Takashimaya and Mitsukoshi, in downtown areas, but they're likely to be much more expensive than the ones at town supermarkets.

If you're living in Japan, you can buy them online.
https://www.google.com/search?sca_esv=088958cbf6397a90&rlz=1C1SQJL_jaJ...

A lot of us locals used to have them made by our grandmothers. Note that hanten is a quilted home-wear for winter. If you want a washable one, be sure you check the tag.

I spotted a few clothes stores in Nakano Broadway but were closed, not sure if they might sell?

Ifd say look for shops geared more towards the elderly. Smaller ones (eg in a traditional shotengai) or potentially something like Ito Yokado.