Kefir isn't whey based, but it does contain some whey, since it's a milk based product. It depends on just how sensitive to whey you are. I'm lactose intolerant, but kefir uses the lactose to culture, so there's very little left in it.
I tried using water kefir in the place of milk kefir and personally, I was less than satisfied with the results in my body. Milk kefir has a lot more beneficial bacteria in it than water kefir - although that may not be the case for everyone.
I don't remember what I spent on my first set of kefir grains. I ended up sending out too many and didn't have enough to start another batch when a dear friend of mine finally asked me for some - so I took her mine.
I finally bought some more kefir grains and was culturing them away, and giving out the excess, and then I messed up and ruined my last set - I got sick and didn't get them 'fed' on time. So I went without kefir (although I did use other probiotics).
I was sooo thrilled when I came across some in my freezer that were really quite old (5 yrs) and figured for the cost of a gallon of milk, I could find out if they would restart - and they did!! I'm back to making my wonderfully thick, rich, yummy kefir again - and my innerds couldn't be happier!!
I understand that kefir isn't for everyone, but I would encourage everyone to at least try it and to understand that if you think that the store bought versions are okay, you will really like the home made kefir!! You have full control over the flavor and the sugar content when you make it yourself - and talk about
easy to make!