Tonkin cane is available at hardware stores as tomato stakes. You just have to look through the bundles to find the good ones. Many are packaged together, so you may have to buy sight unseen, but they are cheap.
There are guys on here that purchase tonkin cane from internet sources. You may want to do a search of this forum to see where they got their material. I would search for "markinengland". He's one of our members that likes using tonkin.
Just be careful... you don't want Pat B angry at you...