Travel through Japan

I plan to go to japan during the summer and was wondering about how much money i should save for the trip, i have done some rough calculation but mostly based on what i "think" so i don't know if it will be enough.

my plan is to go to Fukuoka and travel through maybe 20-30 cities, 1 or 2 days at each city until i reach Sapporo. the trip will be totally spontaneous from day to day so absolutely no planing at all, just waking up and see where the world takes me kind of, hope i don't sound like a hippie haha.
but i just wanna go through the country and see not do all these tourist things.
since i don't do any planing i dont expect to get any good prices on hotels. sometimes i will also sleep in mangacafe to cut down the price a bit.
so what do you guys think my minimum requirement for money is just travel,sleep and food.
the trip will be 25-30 days.
i will buy a JP travel pass or what ever they are called and also i SIMcard so i got internet.

i was thinking something around 5000 USD

I would work on 200usd a day.

JR nationwaide pass wont be suitable as you wont be doing long distances in short periods of time.

Think of regional passes instead of national passes, so they're not as expensive and can last the days you are in the area of coverage. Some very good passes in the JR West and JR East areas, not so much in the Tokai region.

I would think with that goal in mind, you will be taking a lot of short hops. A JR rail pass will likely not ever pay off. The longest one is 21 days, anyway.

I think the $200/day listed above is easily doable if you are actively seeking cheaper accommodations and eating at casual restaurants and convenience stores.

I would look into buses or regional train passes to save money and again, not a national JR rail pass:

https://www.japan-guide.com/e/e2357.html

https://www.japan-guide.com/e/e2366.html

I was traveling through Japan for 2 months with a bicycle but also a lot of public transport and internal Flights and it costed me about 16,000 yen/ day. I always stayed in hotels and was traveling alone. So 200 USD / day should be a good estimation unless you are crazy for shopping. (I did no shopping what so ever as all needed to fit on my small bicycle)

http://bicycletraveljapan.blogspot.com/search/label/Expenses+Practical...

Enjoy your trip to Japan!