Japan food are actually surprising affordable (weak ringgit made it feel expensive), what is the best is that most of the food photos and food models are not for illustration purposes, THEY ARE REAL in portion, well maybe except some fast food chain like McD (still better than here), and of course MOS Burger are still very fulfilling.
Even if we not good at their languages, we can just point at the menu and say: kore kudasai
These are the Bentos from family mart website, they all look exactly the same when we went there

We also love the katsu sandwiches there whether to be in conbini or at the other famous shop, at first we thought egg and katsu sandwiches for 300 yen (RM12) is freaking expensive, but we fell in love with it once we took a bite, their fillings are fulfilling, not like the sandwiches we saw here, front look nice but back side of sandwiches are empty.

Matsuya Gyudon, I am not sure if I am being health conscious as I feel their food too salty.

Those were just my opinion and cheap eatery that I like, I do enjoy all range of food when I went there, from 100 yen per plate of sushi to OMAKASE courses that cost like almost 10000 yen per meal.
Now we also aware that tax has been increased to 10% that not affect on food but affect when you dine-in, if you take away then it is still 8%. When I heard this, I was like is Japan government do this to encourage more rubbish as when take-out the food requires more plastic containers and cutlery compare to dine-in.
In Japan, it is still very hard to find Muslim-friendly food, I did saw some girls with Hijab went into Yoshinoya in Haneda Airport ordered gyudon, but at the same time Yoshinoya there do provide buta-don (pork rice), and they just eat there cheerfully, and many food like snacks in Japan do contain Gelatin that Muslim can't take (got Pork DNA). I am not Muslim, I just have some Muslim friend and they told me this.
Well at least ANA flight that fly from KL or to KL are providing Muslim-friendly food on plane, alcoholic beverage also provided upon request.