Anyone brewing kombucha would be more than happy to share some scoby with you! they usually have too much, and several backups in the fridge/freezer etc.. It's also so easy to divide: you just grab it with your bare (washed, thotoughly rinsed) hands, tear it like a piece of strong cardboard, and any portion would do. you then give it with a bit of the liquid in a bag or jar, and together they will start a culture anywhere...

If i were you I would find a way to call for people around where you live and find one such person, rather than buying anything from a store or such. local auction/second hand sites could be a great place to search. Scobys are often listed for free or just a few bucks....

Also there is something immensely cool when you think of it: you got it from someone, who got it from someone, who... etc. maybe your Scoby is much much older than you?