After trickling out to stores for a couple weeks now, Target has finally posted its listings for Origin Bumblebee and the Worlds Collide 4-Pack. At this time, you can order Origin Bumblebee (limited to 1 per person) but the Worlds Collide 4-Pack is not available at the moment to ship.
For those hunting in stores, these listings can help you determine if local stores by you have the figures in stock. Also, as noted in my Origin Bumblebee review the price of this figure varies widely having been seen for its retail price of $22.99 all the way to $28.99! Use the listing on Target's site for price matching if you find it higher than the $22.99 price.
In a related note, T-Wrecks has begun to hit store shelves but he too is up for order online.
Happy hunting all and best of luck!