Believe it or not, all stevia does not taste the same. After trying several brands (3 or 4)so my husband (who is not into health) would like it too, we decided on Sweet Leaf liquid clear and for the powdered packages Sweet Leaf Stevia Plus.
So far the cheapest places have been iherb.com and webvitamins.com.
As it is I just ordered from Webvitamins this afternoon and they already sent it out. I ordered 5 boxes of a 100 since their shipping is a total of $4.95.
iHerb is cheaper when you just get 1/2 boxes.