Gramzon,
Depends on where you look in Tokyo as to what kind of price you can find. And the more "non-Japanese" style the hotel... the more it will cost you. Business hotels can be found for about $120 USD a night or so.
If you stick to a "hotel" you might find it a little more expensive than if you look at other possible lodging options... like some of the VERY basic ryokan. You can find one for about $70 USD a night or so.
In my spare time I practice Iai. Are you aware of the price to have a Japanese smith to actually fabricate a katana? If you are looking for a genuine Nihonto....... you'll need a mortgage
. And a full custom fabrication will take longer than a couple of weeks.
best,
.................john