What country are you in? Many no longer sell IRC's.
In which case the alternatives are obtaining paper currency for your return country, or their stamps.
There are lots of topics on International return postage so do browse through them {up}

I was wondering for example if you're sending to Ashley Benson she requires postage to send an autograph back, so if you send an Irc is that paying for postage, because I'm not really familiar with the irc system