Local Dairy (Western Dairies) in Spanish Lookout sells 2 kinds of Culture.
CHOOZIT MA 11 LYO 250 DCU @ 52.50 USD + 12.5% tax
CHOOZIT TA 61 LYO 125 DCU @ 42.50 USD + 12.5% tax
They're known to the nice ladies in front as "cheddar culture" and "mozzarella culture". Make sure they bring you the correct package - the help is even less informed than the counter staff.
They also sell bulk liquid rennet for 1.5 USD per ounce.
Reimer's Health Food store in Spanish Lookout carries kefir and yogurt starters from "yogourmet"
Anything else you might need in this beautiful place in terms of consumables or equpment needs to be cobbled together or imported.