Taken from 1-2013 Newsletter :

Within last years the postage got higher and higher. Most DX-clubs put standard contribution to 2 US$. Now we want to show another way and present a real benefit to be a 100% member of International Radio DX Group. For all 100% International Radio members (originals) working an IR-DXpedition (0 or DX) or some special IOTA activations (described on our website), managed by IR-DX HQ QSL service, the contribution is free of charge. This is new rule is valid in 2013 and we hope to continue in 2014. A list of these QSL managers will be published soon. Original IR-DX member means that the DXpedition is worked with your International Radio callsign only.