Amazon has the 4-Pack Kellogg's Froot Loops Variety Pack (10oz boxes) for $11.98 - 5% off with Subscribe & Save (can cancel anytime) - 15% off coupon (check “Save an extra” box, eligible on first S&S order for this product) = $9.58 with free shipping on $25+ or with Prime.

Includes two Froot Loops (10.1 oz boxes) and two Froot Loops with Marshmallows (10.5oz boxes). Roughly $2.47 per box.