How much can I expect to pay to sleep in a non-fancy jjimjilbang (Korean onsen/sento) in a non-touristy area?

You've probably heard of onsens and sentos in Japan, which are public bath houses. Korea has something similar and here they're called "jjimjilbangs".

One major difference is that you usually don't sleep in an onsen or sento in Japan unless it's part of a hotel or resort. But in Korea almost all jjimjilbangs have a sleeping room where you can sleep on the floor (which are always heated in winter).

Now there are very big jjimjilbangs which are practically resorts and have many more facilities than just the baths. Those can be expensive and I'm not asking about those.

But small plain jjimjilbangs are ubiquitous. Every city or town no matter how small has some. These are the ones I'm asking about.

Last time I was in Korea I stayed at one, but that was seven to nine years ago. I forget the price and Korea is a fair bit more expensive now anyway.

I've searched online but can't find recent info in English about the prices to use jjimjilbangs that are not touristy or fancy. The price used to be the same whether you were just bathing or spending the night. I'm not sure if this is standard or if sleeping now costs more.

So, in 2019, what is a typical price to use a low-end jjimjilbang in a random Korean town? Is the price to sleep the same as the price to use?

(I know prices will vary a lot. I'm specifically asking about the cheap ones. I intend to use them as flop houses while long-distance walking and/or hitchhiking in areas that don't get many foreign tourists. I want to know how competitive the prices are compared to cheap backpacker hostels here, which can be as low as 7,000 KRW. I'm well aware that jjimjilbangs are not at all like hostels.)