Where to buy Pocket Wifi and Sim card in Tokyo

The cost of Rental wi-fi router is about 1000 yen per day. Data SIM card is about 2500 yen for 7 days.
If you have one device and travel 7 days, SIM is better. But if you have three devices and travel only 5 days wi-if router is better.

It depends on the number of devices and days of your travel.

For wifi router
This site is cheap. 450 yen per day. 75Mbps 10GB Battery 3 to 4 hours AIr port pick up needs 1620 yen extra
https://en.wifi-rental-store.jp/

This site is average.900 yen per day. 4G 165Mbps Unlimitted Battery 9 hours Free air port pick up.
https://ninjawifi.com/en/plan
I think this is a better device.

If you still want to have SIM. 2400 yen, 1GB, 7days, data only.
https://www.japan-wifi.jp/sim/?agent=PGJ&language=01
You can buy at the airport.

hope this helps

pocket wifi is very useful you can take it to anywhere because it is portable and you can use high-speed internet. you can purchase it online from  https://routertechsupport.net/