GE Capital also offers a program called Care Credit that is accepted at places like dentists, opticians, hearing aid retailers, and veterinarians. I am familiar with it from both sides - I accept it at my veterinary clinic and I have made purchases of medical services and supplies with it. It also offers a six-month same-as-cash option, and my bet is that the terms are the same or quite similar.
I can tell you that they charge the provider a fee that is much in excess of other credit cards, so you should not expect any further breaks on price, shipping, etc.
I will also warn you that if your purchase has not been paid off in full at the exact 6-month cutoff, you will pay a very high interest rate (25 to 30 percent) on the full amount of the purchase all the way back to the purchase date. My advice, if you do it at all, is to immediately start making monthly payments of 20% of the purchase price so that you are certain that the purchase is paid off well before the six-month deadline even after processing times are considered.