These days a lot of people are opting more for AirBnB accommodations over traditional hotels - and an added bonus of this is that many places have a full kitchen (including pots, pans, and dishware) so cooking isn't difficult at all. Here are three easy meals you can pick up at most Japanese supermarkets that are simple to prepare if you've got access to a kitchen!
Yakisoba, literally translated to "fried noodles" is one of the quickest dishes you can prepare, and it's super tasty to boot. You'll find these fresh yakisoba packets at just about every supermarket, for less than a couple of bucks. You get three noodle packets and three flavoring sachets inside - so you can make an individual serving if you choose, or if you're cooking for several people it's easy enough to throw it all in the one pan. You can add whatever veggies you like (we typically use cabbage, carrot and onion - these are also inexpensive veggies in Japan which is helpful) and meat as well if you want to. A popular addition is thinly sliced pork, which you can also pick up at the meat section of the supermarket.
You probably don't want to go buying a big, several kilogram bag of rice if you're only here for a week or two, so a convenient way to have rice to serve along with your curry is to buy some of these microwavable pre-made rice packets. These are the TopValu (Aeon Supermarket Store Brand) variety below - 5 individual servings of 180 grams each is 429 yen including tax.
Gyoza is another quick and easy favorite - these packets at supermarkets are pre-cooked. All you need to do is add some oil to a pan, lightly fry the bottoms, then add some water, cover the pan up and let them steam for a few minutes. These are a steal - there are 20 gyoza in the packet for 170 yen including tax (just over $1.50 US). Serve them up with a side salad and some rice perhaps, and you've got a quick, easy and inexpensive dinner for a few people!
I hope this gives you some quick and easy meal ideas in Japan that won't break the bank at all - and they'll give you a glimpse into what Japanese cuisine consists of!