Widely Available in Asakusa
If you go to Asakusa, the stores lined up behind Kaminarimon, or Thunder Gate, often carry imitation swords you can buy as souveniers for friends or yourself. If you are more interested in acquiring an actual Katana, you will need to look up Katana makers online and expect to pay a few thousand dollars. Actual Katanas take months to make and so they cost a lot.

KurtisW
United States