IVR phone's automated answering/ordering systems question

What would be needed for a cheap IVR system, about what cost? The cheapest I have seen where in the range of 3000-10,000$

Does that include everything one would need to allow a customer to call, place a CC order, check on an order, without human intervention? Or do I need to buy additional items.

I am completely stupid on this subject so any help would be greatly appreciated before I call any company that sales these products I would like some general knowledge to protect myself.