Re: Dojo Floor
If you decide to go with the tires, and you are a non-profit organization, you may be able to get used ones for free from a tire store or auto repair shop. Offer them a receipt on your dojo letterhead. We needed 27 more tires in a hurry and got them this way (thank you, Firestone!)
Watch out that recent tires are generally wider than older ones, and you don't want too huge a diversity of sizes! (We had an interesting time with this, too. It had been ten years since the mat was last redone, and when we added new tires to the old ones, they didn't match.)
In general, if you're a non-profit don't overlook asking for material donations--it's surprising how often you'll get them. I belonged to a church group which needed 20 large sheets to make stage props for an event--someone said, "No problem, I'll ask a hotel to donate them" and to my shock he showed up the next day with 20 large sheets.