This is a culture sharing group, meaning they do not charge for the culture but most people ask for reimbursed shipping. This group is a closed Facebook group, so you will need a Facebook account and you will need to request an invite. This group provides more than just free cultures (water kefir, milk kefir, Kombucha, ACV, Jun, Yogurt, Sourdough) there are also a ton of members willing to help others with their cultures. www.facebook.com/groups/181445115312844/
Sometimes people give grains away for free on Craigslist(www.craigslist.org) and Freecycle(www.freecycle.org). You will want to look at your region for grains for grains near to you. You can even put up a wanted ad to see if someone is willing to donate to you.
This is an large international share list, some people have them for free, some ask for shipping, some want local pickup only and some even ask for money: http://www.torontoadvisors.com/suppliers
Grains can be purchased from many different sites:
www.etsy.com – Water Kefir, Milk Kefir
www.cragislist.org – Water Kefir, Milk Kefir
www.ebay.com – Water Kefir, Milk Kefir
www.amazon.com – Water Kefir, Milk Kefir
www.yemoos.com – Water Kefir, Milk Kefir, yogurts, Authentic Ginger Beer Plant, SCOBYs. This site also contains recipes and information on how to care for your cultures.
www.kefirlady.com – Water Kefir, Milk Kefir, Kombucha. She feeds her milk kefir grains raw goat’s milk, in case anyone wants grains that are not grown in cow’s milk.