Expenses during a Japanese holiday

I saw somewhere that prices tend to elevate during the holidays. I'm traveling to Japan in mid-August, right after the Obon celebration, should I expect to spend more on food and trinkets/souvenir? Any help would be greatly appreciated. By the way, I'll be staying in the Toyosu area. Thank you

Tickets and food are standard prices, they should not increase - imagine if your local convenience stores, public transport systems and museums increased prices just for a high tourism season! Souvenir prices may increase if the sellers want to cash in on the greater numbers of tourists, but I doubt it - they will be doing extra trade already and will still want to compete with other souvenir sellers. You should worry more about crowds.

Thank you for your response. I figured that would be the case, just wanted to be able to tell the wife.

Accommodation (particularly ryokan) commonly charge more on weekends and on big holidays. Regular hotels may also end up being more expensive because any early cheap deals will be snapped up.

You can see what I mean by playing with the reservation software on hotel websites (or on popular booking sites like rakuten, etc)and changing dates.

In that respect, it's just like in Europe. Supply and demand.