^Yes, they do, but the new change is not only for odd-shaped items. The new system, Shape Based Pricing, will take the weight & dimensions of all types of packages into account. Here's some useful info: PDF of Rates & Fees / FAQs / In-Depth PDF about the changes Random things: +For example, in First-Class Mail, a 2-ounce letter will cost $0.58; a 2-ounce flat, $0.97; and a 2-ounce parcel, $1.30. +Letters can now only go up to 3.5oz. Heavier and they will be charged the flats (large envelopes) rate. +Priority Flat-Rates: Envelopes - $4.50 Boxes - $9.15 +First Class: The first ounce increases to $0.41, but the additional ounces decrease to $0.17.