Ziploc has now gone BPA Free on their plastic storage containers. I was able to pick up a couple from my local Wal-Mart for $2.48 for a set of 4. The "regular" storage containers were $1.97 so it was less than a dollars difference for my comfort and sanity.
Located below is an article you might want to check out on BPA and the facts that aren't known.
picture shown is not of actual Ziploc containers