Newneys:

Protect Cream: 5x Defense (Available at later part of the game)
Can of Oden: 1.25x Attack
Can of Ramen: 1.25x Attack
Chicken Kebab: 1.25x Drop Rate
Exclusive Drink: 1.1x Random Stat
Exclusive Dessert: 1.1x Random Stat

Gamers Main Store:

"GAMERS" Exclusive Raffle Ticket: 1.1x Random Stat
Souvenir with Cutesy Character Art: 1.1x Random Stat

Yamata Denki:
Mouse Pad: 1.1x Defense
Remote-shaped Gamepad: 1.1x Attack

Tokiwamusen:

Edutainment Game: 1.2x EXP
Shooting Game: 1.25x EXP

sofmap Hon-kan:

Cyclone Vacuum Cleaner: 1.35x Drop Rate
Electronic Dictionary: 1.25x EXP

Toranoana Akihabara Store A (Not worth purchasing from here):

Indie Doujin Comic: 1.1x EXP - 12000yen
Self-Published Comic: 1.2x Attack Stat - 50000yen

animate Hon-kan:

Popular Anime Theme Song CD Single: 1.15x Attack Stat
"animate" Exclusive Raffle Ticket: 1.1x Random Stat

Lammtara Epixis Akiba:

Gravure Idol's Photo Book: 1.2x Attack Stat
Sakura Iro Club X's Live BD: 1.35x Drop Rate

Hon Quixote:

Economical Confectionary: 1.1x Random Stat
Adjustable Dumbbells: 1.15x Attack Stat

Akiba sofmap No.1 Store

AKW Steamed Bun: 1.1x Random Stat
AKW CD: 1.25x Random Stat


TRADER Main Store
Trading Card: 1.3x Attack Stat
Old Portable Gaming System: 1.1x Defense Stat

Yodobashi Akiba:

Action Movie DVD: 1.1x Attack Stat
Binoculars: 1.2x Drop Rate

Dospara Akihabara Main Store:

Can of Ramen: 1.25x Attack Stat
Shorts Guide (Normal): Strip EXP UP
Shorts Guide (Rare): Strip EXP UP (Available at later part of the game)
Latest OS from DSP: 1.75x EXP
Geiger Counter: 1.35x Drop Rate