Components
* Transport: $1100 * Accommodation: $380 * Food: $375 * Communication: $60 * Entertainment: $60 * Goods: ??? * Shipping stuff home: $80
Total: $2055 plus whatever we spend on goods.
Transport
* Airfares estimated to be $603 * JR pass should be $476 * Non-JR travel will cost extra, but probably not much.
Call it $1100 for now.
Accommodation
* Nagoya for 2 nights will be ??? * Airbnb accommodation in Naka-Meguro will be about $290
Estimate $380
Food
Guessing $25 per day.
Estimate $375 after adding some fudge factor.
Communication
Phone rental and data SIM purchase?
Maybe $60 depending on how we do it.
Entertainment
Mostly arcade games and anything to kill time.
Estimate $60
Goods
- Otaku goods
- Cosplay goods
- Souvenirs and stuff that people requested
- Some may be repaid later
Impossible to estimate, assume hundreds of dollars 
Shipping stuff home
Call it $80 for now, may not be necessary at all.