Tires are expensive. We bought 4 recently... it's not as though you can buy just one tire. I suppose that's why there are place like this that sell 4 tires that are used. I went to Costco and got 4 new.
As an educator, I use technology to shape the experience of each of my students. I teach elementary music, and have a series of video tutorials for students at k5tunes.com. I am also an instructor at Azusa Pacific University in the Ed Tech program, and at University of La Verne in the Child Dev. program.
I write about how technology is shaping the face of modern education at billselak.com. I am a co-organizer of EdCampSFBAY and EdCampOCLA, a collaborative, participant-driven conference for educators.