I know this thread is old... but I'll post anyway!
It's illegal to take them at free or discounted prices for Deaf/hh people, cause the goverment puts out that money for the products and interpreters to work, that's how the companies make money (from the goverment) if the Deaf community pays nothing. They work as VRS (video relay services) where you can call a hearing person through the use of a vp interpreter, and they work as basic VP's where you can call another Deaf/hh person and see eachother directly.
Some companies do sell them for hearing people. I know "ZVRS" which is one of the best running companies (imo), plus it is Deaf owned (which I will always support any Deaf owned business, especially if it's for the Deaf community)... well they have some pretty cool ones. They are portable (unlike sorenson) and they can connect to your TV too for large viewing (like Sorenson). The drawback is that some of them are hundereds of dollars for hearing coustomers, plus you have to pay a monthly or anual fee for the services (ie. interpreters, talk time, & voicemail) even if you don't use them. It is well worth it in my opinion though: I have one (& pay all the fees too) since I have many Deaf friends that I like to chat with occasionally (even though we mainly just text), and my bf is deaf too, so we do what we call "VP dates". Plus I babysit some kids (Deaf & hearing) and when it is a good tool to have them practice and learn on. I always make the kids order the pizza by themself & let them help me make business calls, just as a learning expirence, so that they can all be independent one day (& it is a cool expirence for the hearing kids who know sign... never know maybe it will spark an interest to work fora vrs company one day).
Most companies won't shoot you down if you, as a hearing person, illegally download the free pc (computer) vrs/vp programs. But the goverment will come knocking on your door if they catch a hearing person taking advantage (without paying full price) of their products specifically paid for and designed for Deaf customers with fancy features like tv hook up & portable wifi. That is a convenience and luxury for Deaf people, it helps them call 911 if there is an emergency (since you cannot text 911 in all areas) and they are not home, it also help them make business calls at work and some use the interpreter directly like if they are at a doctors appointment or meeting an accountant. It is like a virtual interpreter as opposed to a physcial person interpreter (which they should still stay in business and be hired, but desperate situations arrise sometimes for non-oral Deafies, where you cannot wait for an interpreter and would prefer easy communication over writing on paper or playing sharades)