I'm writing this post while lying on my hotel bed on my last vacation day in Japan because I can't wait to share the tips and tricks.
I came to Japan for free-and-easy holiday with my other 5 family members and we decided since the beginning of the trip that we'll go frugal. That's because we heard so much word of mouth that everything in Japan is expensive. But after having the trip myself for the past 11 days, I can tell you that you can still enjoy Japan in budget.
Here are the tips on saving money in Japan:
Go for good and reliable airlines for extra comfort since you're going to have 7-8 hours flight. And look out for promotions at least 2-3 months before your trip. I booked my air tickets in June or July (I can't remember exactly). That time Singapore airlines was having big promotion for 2 weeks or so. So me & my sister checked the best schedule & price intensely for few days and booked quickly once decided (and before it's gone). We got it a good deal, less than < $700/pax for round trip flight, including travel insurance.
I recommend you to book your accommodation at travel agent because the rate is cheaper than the published rate. Additionally, you can ask for recommendation for best location and best priced hotels especially when you're not familiar. I booked my accommodation at JTB Singapore. I'm satisfied with their service because they really generous in giving information. They gave me the shuttle bus schedule information and map how to go to the day tour pick-up point even though I didn't ask for it.
Since my family members are not big eater, we often buy just few different menu and share among us. We even went to nearby department store to buy few boxes discounted bentos to be shared for dinner. Usually the discount starts after 5pm. We bought the not so expensive ones that cost around ¥450-¥650 per box. One box is good to be shared by 2 persons so we save 50% mostly on food.
We traveled a lot on trains and buses. I don't recommend day pass since you will be spending most time in a day at the places of attractions or shopping places. Within city, buying normal train ticket at the ticketing machine is good enough. Try to avoid taxi unless really necessary as it can be quite pricey.