I'm not sure what to suggest, but I will offer this. When you say you want the lowest cost, you might end up with something like the calls I get where you can barely hear what the caller is saying because of poor quality equipment. What is funny is when they are trying to sell me telecommunications service. Yeah, I'd buy that (NOT!). If people hang up on you out of frustration, it's costing you more that you could ever save with cheap quality.