Alternately, purchase four boxes of "This or That?" Pop-Tarts with the 50%-off Cartwheel offer and use this printable coupon for $1 on any four Pop-Tarts toaster pastries (Kellogg's Family Rewards account required, free to join) for a net cost of $4.48 for 48 toaster pastries, or $1.12 per 12-ct box.
The KFR coupons page also has a 40? coupon on one box of Pop-Tarts, but it is supposed to be limited to the new Frosted Chocolatey Caramel variety. However, you may be able to apply it to the purchase of a box of the "This or That?" Pop-Tarts without override. Combined with the Cartwheel offer, the net cost becomes 97? per box.
Improve any of the deals further by using your Target REDcard to save an additional 5% on the purchase.