I spend 100$ a day on food and random stuff and I'm not even on vacation lol, this is everyday life.
I go out with my gf to eat nearly every night, that's about 6000yen just for that. Then lunch and whatever else I do quickly adds up to 100$ easily.
My lifestyle is decent though.
If I were visiting Japan, I'd budget 200$ a day excluding hotels, most days you'll spend only 100 but you need to know that when something is expensive, it's like nose-bleed expensive, and tourists often get sucked into them.
By the way, price differences between lunch meals and dinner meals are huge!
The kushikatsu place near my house which I love to death is 1200yen for all you can eat 70mins + 210yen for all you can drink at lunch time. For dinner it's 2500yen all you can eat, and there's a silly little dish of nonsense everyone has to buy that costs like 300yen per person. More than double easily! And this is a low-end restaurant, not even close to a pricey or nice place.
I recommend eating out for lunch (or breakfast if you are waking up on holiday-schedule
and eating in for dinners, convenience store foods are quite good actually compared to what I was used to in the west.
If you take taxis, there's a new kind of taxi these days with a 500 on the roof, they are WAY cheaper than all the other ones, the starting fare is 500yen and the meter goes up much much slower.