Mailing tube/art tube in Tokyo?

I'm in Tokyo till this coming Saturday (9/11/10) and have purchased some pieces of artwork and I need to find an art tube (preferably plastic) since i'm afraid they might be damaged. I am staying at the Hotel new Hankyu by St. Lukes hospital. Where would I have to go to get one at a good price?

Try TOKYU HANDS, they are all over Tokyo but I think Ginza I think is your nearest branch...
http://ginza.tokyu-hands.co.jp/

(Shibuya has a bigger branch if you want more choice)

I think Ginza Ito-Ya and Sekaido sell these products.

http://xrl.us/bhyiyp (Link to maps.google.com)

#9 Ginza Ito-ya
#10 Sekaido

In addition to Tokyu Hands,there is also a place called LOFT, which has a pretty extensive artwork/supply section that should have what you need. If you have no luck, maybe try a shop in Akihabara that sells posters and ask if you can have a spare tube cheap or for free. good luck!