Walgreens has Nature's Bounty Vitamin D on sale for $5 with a $5 Register Reward--so free!
It gets better, though! Register here and you can print up to four copies of a $2/1 coupon (after each print hit the back button & then refresh to print again). So get four bottles for $3 each, and get a $5 Register Reward for each one. Be sure to only buy 1 per transaction because you'll only get the Register Reward 1 time per transaction.
Four transactions = $8 moneymaker!
If you live on the East Side, the Milwaukie location just off Hwy. 224 just restocked and they have over 100 bottles to sell by Saturday night. Some stores will limit the number of transactions of "free after Register Reward" transactions you can do, but Milwaukie is not limiting this time so they can move these!