Pitney Bowes introduced the colorful flag sheet of 10 in 2011 from its self-service kiosks. The kiosk can print stamps with imprint of First Class Mail, Postcard or nothing. The values can be printed between 29C and $99.99.
Here offers a postcard with 29C flag stamp printed and mailed on 1/22/2012. It is the very last day of this rate for postal card.

Buyers pay $1 within US or $2 worldwide at buyer's risk. Insured or registered mail is optional with additional cost. Shipping to US with tracking is $4. Registered airmail will add $16 for international buyers. You are agreed to take the risk of lost mail if you do not select tracking/insurance/registration. Insurance or registration is required for invoice at $100 or above unless agreement reached with buyer. Will combine shipping.