need click to call webrtc, voip setup

I am providing sales & support to my customers who come to my website. I need to set up something with which customers can call me directly from my website and i can receive their calls via my browser or admin panel or any customized app or android phone softphone or app. clet me know how you can help configure this. 1) I am looking for a preferably free soft phone solution could be freeswitch or webrtc,zoiper or whatever as far as my basic requirement is met. 2) what will be the infrastructure needed ie. linux machine etc. 3) will they be able to directly call me from my website. Please share any demo or sample snapshots to better understand Kindly explain in as many details if possible or let know if you have any questions