Can I use two hardware SIP Phones to make free calls between India and Saudi Arabia?

I want to make VOIP calls between India and Saudi Arabia. I want to know if buying two SIP phones (hardware) and placing one in each country will be enough to do this or do I have to subscribe for the VOIP service from some service provider who will bill me on a per minute basis? If the VOIP service provider is not necessary to make such calls, then will the calls made using only the hardware SIP phones be free?
Douglas: Does skype offer hardware phones? PC to PC calling is free in Skype, but is hardware phone to hardware phone free? I know that calling to traditional PSTN numbers is chargeable in Skype. What about hard phone hard phone ? If free, where can I find the phones offered by skype? If at all, do they charge you monthly or yearly for the use of their service. I would like to add I prefer a free service, between to hard phones placed in different countryes.
Douglas: Does skype offer hardware phones? PC to PC calling is free in Skype, but is hardware phone to hardware phone free? I know that calling to traditional PSTN numbers is chargeable in Skype. What about hard phone hard phone ? If free, where can I find the phones offered by skype? If at all, do they charge you monthly or yearly for the use of their service. I would like to add I prefer a free service, between to hard phones placed in different countries.