Can You Use a Voip Type Service Without Paying or Needing Special Equipment? I Want to Use My Pc as My Home Ph

To address each part of your question...

"Without Needing Special Equipment"
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Yes, you can get VoIP type service without needing any special equipment. There are two types of VoIP - VoIP Services and VoIP Softphones. VoIP Services are the ones such as Vonage and Packet8 that utilize a standard telephone to make calls. A VoIP Softphone is one that is a piece of software on your computer. You then use the speakers and microphone of your computer to make and receive calls (using a headset or USB phone is recommended though). Examples of a Softphone would be Skype or PalTalk. This page has some expamples of hardware you can use with softphones...
http://www.voipan.com/voip-phones/

Without Paying
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While there are some free VoIP softphones out there such as Jajah, they have limitations and inconveniences that outweigh negatively the benefits of others that ask for only a very small amount of money. Here is a page that lists a bunch of softphone service providers that are very inexpensive...
http://www.voipan.com/internet-phones/