Most radio stations I've ever dealt with have people who assist with this kind of stuff, telling you exactly what to buy. There's a world of difference out their. Some people will need to sound the same as the studio - so they may suggest a mic type, and how you get the audio to them. Other people, like voice over specialists will have a small studio with a variety of kit that allows them to do the day to day jobs they get.
If your 'broadcaster' deems a cheap tinny headset and Skype adequate, then it will be a dirt cheap solution. If they need you to fund your own ISDN line, then the budget is perhaps hundred times higher. Where in this you need to sit, we have no idea.