My Post Office stopped selling them over a year ago.
I guess it was just a matter of time before it became National

I have some very bad news. As of Jan. 27, 2013, the United States Postal Service has discontinued the sale of International Reply Coupons.
[b]Statement by the USPS below:[/b]
[i]"International Reply Coupons: The Postal Regulatory Commission (PRC), in its PRC Order No. 1541, approved the Postal Service’s proposal to discontinue outbound international reply coupons effective January 27, 2013; however, the Postal Service will continue to exchange (redeem) international reply coupons purchased in foreign countries and presented at U.S. Post Office™ facilities."[/i] -[b]Source:[/b][url]http://about.usps.com/postal-bulletin/2012/pb22352/html/updt_005.htm[/url]

This means that if you are out of IRCs, you're going to have to trade stamps. I believe that you can still ask your local post office if they have any unused IRCs. Though, the price for them is $2.20, instead of $2.10. [b]Source:[/b][url]http://about.usps.com/postal-bulletin/2012/pb22329/html/info_003.htm[/url]

Here is a list of other countries that exchange and/or sell IRCs:[url]http://www.upu.int/en/activities/international-reply-coupons/countries-selling-ircs.html[/url]

Note: I am willing to trade (not sell; I do not do Pay Pal or cash. I might take checks.) any US stamps with anybody, as long as you will be honest. I will always be an honest trader/seller.