While visiting The Brick Blog to provide a link, I noticed a post saying that ToysRUs.com is currently selling Series 4 Collectible Minifigures online! The post was this morning, but it appears they still have them in stock. They are retailing for $2.99 USD and there don't appear to be any limits. Right now Toys R Us will ship for free on orders above $75. Head on over to TRU.com for more details.
Thanks once again to The Brick Blog for the news.